经典SQL语句集锦

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数据库sql查询语句大全

数据库sql查询语句大全

数据库sql查询语句大全数据库SQL查询语句是用来从数据库中检索数据的命令。

以下是一些常见的SQL查询语句大全:1. SELECT语句,用于从数据库中选择数据。

例如,SELECT FROM 表名;2. WHERE子句,用于过滤数据,只返回满足特定条件的行。

例如,SELECT FROM 表名 WHERE 列名 = '条件';3. ORDER BY子句,用于对结果集按照指定列进行排序。

例如,SELECT FROM 表名 ORDER BY 列名;4. GROUP BY子句,用于对结果集按照指定列进行分组。

例如,SELECT 列名1, 列名2 FROM 表名 GROUP BY 列名1;5. HAVING子句,用于过滤分组后的数据。

例如,SELECT 列名1, COUNT(列名2) FROM 表名 GROUP BY 列名1 HAVING COUNT(列名2) > 10;6. JOIN子句,用于在多个表之间建立关联。

例如,SELECT FROM 表名1 INNER JOIN 表名2 ON 表名1.列名 = 表名2.列名;7. UNION操作符,用于合并两个或多个SELECT语句的结果集。

例如,SELECT 列名1 FROM 表名1 UNION SELECT 列名2 FROM 表名2;8. INSERT INTO语句,用于向数据库表中插入新记录。

例如,INSERT INTO 表名 (列1, 列2) VALUES (值1, 值2);9. UPDATE语句,用于更新数据库表中的记录。

例如,UPDATE 表名 SET 列名 = 值 WHERE 条件;10. DELETE FROM语句,用于从数据库表中删除记录。

例如,DELETE FROM 表名 WHERE 条件;以上是一些常见的SQL查询语句,它们可以帮助用户从数据库中检索、过滤、排序、分组和更新数据。

当然,SQL语言还有很多其他的功能和语法,这些只是其中的一部分。

SQL查询语句大全集锦

SQL查询语句大全集锦

SQL查询语句大全集锦一、简单查询简单的Transact-SQL查询只包括选择列表、FROM子句和WHERE子句。

它们分别说明所查询列、查询的表或视图、以及搜索条件等。

例如,下面的语句查询testtable表中姓名为“张三”的nickname 字段和email字段。

代码:SELECT `nickname`,`email`FROM `testtable`WHERE `name`='张三'(一) 选择列表选择列表(select_list)指出所查询列,它可以是一组列名列表、星号、表达式、变量(包括局部变量和全局变量)等构成。

1、选择所有列例如,下面语句显示testtable表中所有列的数据:代码:SELECT * FROM testtable2、选择部分列并指定它们的显示次序查询结果集合中数据的排列顺序与选择列表中所指定的列名排列顺序相同。

代码:SELECT nickname,email FROM testtable3、更改列标题在选择列表中,可重新指定列标题。

定义格式为:列标题=列名列名列标题如果指定的列标题不是标准的标识符格式时,应使用引号定界符,例如,下列语句使用汉字显示列标题:代码:SELECT 昵称=nickname,电子邮件=email FROM testtable4、删除重复行SELECT语句中使用ALL或DISTINCT选项来显示表中符合条件的所有行或删除其中重复的数据行,默认为ALL。

使用DISTINCT选项时,对于所有重复的数据行在SELECT返回的结果集合中只保留一行。

5、限制返回的行数使用TOP n [PERCENT]选项限制返回的数据行数,TOP n说明返回n 行,而TOP n PERCENT时,说明n是表示一百分数,指定返回的行数等于总行数的百分之几。

代码:SELECT TOP 2 * FROM `testtable`代码:SELECT TOP 20 PERCENT * FROM `testtable`(二) FROM子句FROM子句指定SELECT语句查询及与查询相关的表或视图。

sql经典语句(SQLclassicsentences)

sql经典语句(SQLclassicsentences)

sql经典语句(SQL classic sentences)I. Basic operation1) DESC, the describe role is to display the structure of the data table using the form: desc data table name2) distinct eliminates duplicate data usage: select, distinct, field name, from data table3) order by field 1 ASC, field 2 desc4) nested queries select, emp.empno, emp.ename, emp.job, emp.salFrom scott.empWhere sal>= (select, Sal, from, scott.emp, where, ename='WARD');5) nested queries select, emp.empno, emp.ename, emp.job, in, emp.salFrom scott.empWhere, Sal, in (select, Sal, from, scott.emp, where, ename ='WARD');6) nested queries select, emp.empno, emp.ename, emp.job, any, emp.salFrom scott.empWhere Sal > any (select, Sal, from, scott.emp, where, job='MANAGER');Equivalent to (1) select, Sal, from, scott.emp, where, job ='MANAGER'(2) select, emp.empno, emp.ename, emp.job, emp.salFrom scott.empData found in where Sal > (1) data a, or, Sal > (1), data found in B, or, Sal > (1), CEg:Select, Sal, from, scott.emp, where, job ='MANAGER'results; 12,10,13Equivalent to sal=12,10,13 or SAL> (12, OR, 10, OR, 13)7) the intersection operation is the intersection concept in the set. The sum of the elements that belong to the set A and belongs to the set B is the intersection. In the command edit area, execute the following statement.Eg:(select, djbh, from, ck_rwd_hz) intersect (select, djbh, from, ck_rwd_mx) documents numbered the sameSelect * from ck_rwd_mx a,((select, djbh, from, ck_rwd_hz) intersect (select, djbh, from, ck_rwd_mx)) BWhere a.djbh =b.djbhTwo function1) ceil takes the minimum integer ceil (N) greater than or equal to the value N; select, Mgr, mgr/100, ceil (mgr/100), from, scott.emp;2) floor takes the maximum integer floor (N) less than or equal to the value N; select, Mgr, mgr/100, floor (mgr/100), from, scott.emp;3) the remainder of mod m divisible by mod (m, n) n4) power, m, N, square, mod (m, n)5) round m four, five, keep the n bit mod (m, n)Select round (8.655,2) from dual; 8.66Select round (8.653,2) from dual; 8.656) sign n>0, take 1; n=0, take 0; n<0, take -1;7) AVG averages AVG (field name)8) count statistics total count (field name) select (*) from scott.emp; select count (distinct job) from scott.emp;9) min calculates numeric fields minimum, select, min (SAL), minimum salary from scott.emp;10) max calculates numeric field maximum, select, max (SAL), highest salary from scott.emp;11) sum calculates the sum of numeric fields, select, sum (SAL), the sum of salaries, from, scott.emp;Three input data1) single data entryInsert into data tables (fields 1, fields 2,...) valuse (field name 1 values, field name 2 values,...)Numeric fields can write values directly; character fields add single quotation marks; date fields add single quotes; at the same time pay attention to the order of days and months2) multi line data entryInsert into data table (field name 1, field name 2,...)(select (field name 1 or operation, field name 2 or operation,...) from data table where condition)3) data replication between tablesCreate table scott.testAs(Select, distinct, empno, ename, hiredate, from, scott.emp, where, empno>=7000);Create table spkpk_liu as select * from spkfk; creates tables and copies data, but creates incomplete table informationThis is all the way to full table backups.Usually after the table is built, you need to see if you want to build the index and primary key again.And "create, table, spkpk_liu, as, select * from, spkfk.""After this table is built, many of the parameter values of the table are the default minimum values, such as the initial value of the original table 10M, and the new table is probably only 256K.Formal environment used in the table, generally do not recommend such a table built.In this way, just a little lazy, if you do so,A statement can achieve the purpose of building tables and inserting data.For example, you need to modify the data in table A, and you might want to back up the data from the A table before you modify it.This time you can use create table... As...This makes it easy to retrieve data from the A table in the futureYou can do this when you debug your own program, but you can't create processes, packages, functions like thisFour delete dataDelete deletes data; truncate deletes the entire table data, but retains the structure1) delete recordsDelete from scott.test where empno and empno <=8000 > = 7500;2) delete the entire dataTruncate table scott.test;Similarities and differences between truncate, delete and dropNote: the delete here refers to the delete statement without the where clauseThe same thing: truncate and the delete without the where clause, and drop will delete the data in the tableDifference:1. truncate and delete only delete data and do not delete the structure of the table (definition)The drop statement will delete the structure of the table, the dependent constraints (constrain), the trigger, and the index (index); the stored procedure / function that depends on the table will be retained, but the invalid state will be changedThe 2.delete statement is DML, which is put into the rollback segement before the transaction is committed, and if you have the corresponding trigger, the execution will be triggeredTruncate, drop is DDL, the operation takes effect immediately, and the original data is not put into the rollback segment and cannot be rolled back. The operation does not trigger trigger.. Obviously, the drop statement releases all the space occupied by the table3. speed, in general: drop>, truncate > deleteOn use, you want to delete part of the data rows, with delete,take care to bring the where clause. The rollback section is large enough to be rolled back through the ROBACK, and there is considerable room for recoveryTo delete tables, of course, use dropYou want to keep the table and delete all the data. If you have nothing to do with the transaction, you can use truncate. Truncate, table, XX, delete the entire table of data, there is no room for recovery, the benefits can be arranged in the table debris, release spaceSo it's better to back up the data firstIf you are tidying up the inner fragments of a table, you can use truncate to catch up with reuse stroage and then import / insert data againFive update dataUpdate data sheetSet field name, 1=, new assignment, field name, 2=, new assignment,...Where conditionUpdate scott.empSet, empno=8888, ename='TOM', hiredate='03-9, -2002'Where empno = 7566;Update scott.empSet sal=(select, sal+300, from, scott.emp, where, empno = 8099)Where empno=8099;Decode (condition, value 1, translation value 1, value 2, translation value 2, value n, translation value n, default value)Six data export1 export the database TEST completely, export the user name system password manager to D:\daochu.dmpExpsystem/manager@TESTfile=d:\daochu.dmp full=y2 export the system user in the database to the table of the sys userExpsystem/manager@TESTfile=d:\daochu.dmp only wner= (system, Sys)3 export tables table1 and table2 from the databaseExpsystem/manager@TESTfile=d:\daochu.dmp tables= (table1, table2)4 export the field filed1 in the table table1 in the database to data that starts with "00"Expsystem/manager@TESTfile=d:\daochu.dmp tables= (table1) query=\ "where filed1 like'00%'\""Explmis_wh/lmis@lmisbuffer=10000 only WNER=lmis_wh rows=nfile=d:\lmis_wh_nodata.dmp log=d:\lmis_wh_nodata.logImplmis/lmis@lmisbuffer=10000, fromuser=lmis_wh, touser=lmis, file=d:\lmis_wh_nodata.dmp, log=d:\lmis_wh_nodata.logC:\>implmis/lmis@lmisbuffer=50000000, full=n,file=e:\daochu.dmp, ignore=y, rows=yCommit=y compile=y fromuser=lmis_wh touser=lmisSeven data import1 import data from the D:\daochu.dmp into the TEST database.Impsystem/manager@TEST file=d:\daochu.dmpThere may be a problem with it because some tables already exist, and then it is reported wrong, and the table is not imported.It's OK to add ignore=y at the back.2 import table table1 from d:\daochu.dmpImpsystem/manager@TEST file=d:\daochu.dmp tables= (table1)SQL definition: SQL is a database oriented general data processing language specification, can complete the following functions: data extraction query, insert modify delete data generation, modify and delete database objects, database security, database integrity control and data protection.SQL classification:DDL - Data Definition Language (CREATE, ALTER, DROP, DECLARE)DML - Data Manipulation Language (SELECT, DELETE, UPDATE, INSERT)DCL - data control language (GRANT, REVOKE, COMMIT, ROLLBACK) DDL - database definition language: direct submission. CREATE: used to create database objects.DECLARE: in addition to creating temporary tables that are used only during the process, the DECLARE statements are very similar to the CREATE statements. The only object that can be declared is the table. And must be added to the user temporary tablespace.DROP: you can delete any object created with CREATE (database object) and DECLARE (table).ALTER: allows you to modify information about certain databaseobjects. Cannot modify index.Eight, the following is mainly based on object presentation of basic grammar1, database:Create database: CREATE, DATABASE, database-name, [USING, CODESET, codeset, TERRITORY, territory]Note: the code page problem.Delete database: drop, database, dbname2, table:Create new table:Create, table, tabname (col1, Type1, [not, null], [primary, key], col2, type2, [not, null],...)Create a new table based on the existing table:A:create, table, tab_new, like, tab_oldB:create, table, tab_new, as, select, col1, col2... From tab_old definition onlyModify table:Add a column:Alter, table, tabname, add, column, col, typeNote: column added will not be deleted. The DB2 column after the data type does not change, the only change is to increase the size of the varchar. Add primary key:Alter, table, tabname, add, primary, key (Col)Delete Primary key:Alter, table, tabname, drop, primary, key (Col)Delete table: drop, table, tabnameAlter table BMDOC_LIUFDrop constraint PK1_BMDOC cascade;3, table space:Create table spaces: create, tablespace, tbsname, PageSize, 4K, managed, by, database, using (file, file, size)Adding containers to tablespace: alter, tablespace, tablespace_name, add (file,'filename', size)Note: the operation is irreversible and will not be removed after adding the container. Therefore, when it is added, pay attention to it.Delete tablespace: drop, tablespace, tbsname4, index:Create indexes: create, [unique], index, idxname, on, tabname (col... ).Delete index: drop, index, idxnameNote: the index is not modifiable. If you want to change it, you must delete it.5 views:Create views: create, view, VIEWNAME, as, select, statementDelete view: drop view VIEWNAMENote: the only change to the view is the reference type column, which changes the range of columns. None of the other definitions can be modified. The view becomes invalid when the view is based on the base table drop.DML - the database manipulation language, which does not implicitly submit the current transaction and is committed to the setting of the visual environment.SELECT: querying data from tablesNote: the connection in the condition avoids Cartesian productDELETE: delete data from existing tablesUPDATE: update data for existing tablesINSERT: insert data into existing tablesNote: whether DELETE, UPDATE, and INSERT are submitted directly depends on the environment in which the statement is executed.Pay attention to the full transaction log when executing.2, DELETE: delete records from the tableSyntax format:DELETE, FROM, tablename, WHERE (conditions)3, INSERT: insert a record into the tableSyntax format:INSERT INTO tablename (col1, col2),... ) VALUES (value1, Value2),... );INSERT INTO tablename (col1, col2),... ) VALUES (value1, Value2),... ) (value1, value2,... ),......Insert does not wait for any program and does not cause locking4, UPDATE:Syntax format:UPDATE tabname SET (col1=values1, col2=values2),... (WHERE) (conditions);Note: update is slower and requires indexing on the corresponding column.Nine permissionsDCL - Data Control LanguageGRANT - Grant user permissionsREVOKE - revoke user rightsCOMMIT - commit transactions can permanently modify the databaseROLLBACK - rollback transactions, eliminating all changes made after the last COMMIT command, so that the contents of the database are restored to the state after the last COMMIT execution.1, GRANT: all or administrators assign access rights to other usersSyntax format:Grant [all privileges|privileges,... On tabname VIEWNAME to [public|user |,... .2 and REVOKE: cancel one of the user's access rightsSyntax format:Revoke [all privileges|privileges,... On tabname VIEWNAME from [public|user |,... .Note: any permissions of users of instance level cannot be canceled. They are not authorized by grant, but are permissions implemented by groups.3, COMMIT: permanently records changes made in the transaction to the database.Syntax format:Commit [work]4, ROLLBACK: will undo all changes made since the last submission.Syntax format:Rollback [work]Ten advanced SQL brief introductionFirst, the query between the use of computing wordsA:UNION operatorThe UNION operator derives a result table by combining two other result tables (such as TABLE1 and TABLE2) and eliminating any duplicate rows in the table.When ALL is used with UNION (that is, UNION ALL), the duplicate rows are not eliminated. In the two case, each row of the derived table does not come from TABLE1, or from TABLE2.B:EXCEPT operatorThe EXCEPT operator derives a result table by including all rows in TABLE1, but not in TABLE2, and eliminating all duplicate rows. When ALL is used with EXCEPT (EXCEPT ALL), the duplicate rows are not eliminated.C:INTERSECT operatorThe INTERSECT operator derives a result table by including only rows in TABLE1 and TABLE2 and eliminating all duplicate rows. When ALL is used with INTERSECT (INTERSECT ALL), the duplicate rows are not eliminated.Note: several query results lines using arithmetic words must be consistent.Appendix: introduction to commonly used functions1, type conversion function:Converted to a numeric type:Decimal, double, Integer, smallint, realHex (ARG): 16 hexadecimal representation converted into parameters.Converted to string type:Char, varcharDigits (ARG): returns the string representation of Arg, and Arg must be decimal.Converted to date or time:Date, time, timestamp2, time and date:Year, quarter, month, week, day, hour, minute, secondDayofyear (ARG): returns the daily value of Arg in the yearDayofweek (ARG): returns the daily value of Arg in the weekDays (ARG): the integer representation of the return date, the number of days from the 0001-01-01.Midnight_seconds (ARG): the number of seconds between midnight and arg.Monthname (ARG): returns the month name of arg.Dayname (ARG): the week that returns arg.3 string function:Length, lcase, ucase, ltrim, rtrimCoalesce (arg1, arg2)... ) returns the first non null parameter in the argument set.Concat (arg1, arg2): connect two strings, arg1 and arg2.Insert (arg1, POS, size, arg2): returns a arg1 that removes size characters from POS and inserts arg2 into that location.Left (Arg, length): returns the leftmost length string of arg.Locate (arg1, arg2, &lt, pos>): find the location of the first occurrence of arg1 in arg2, specify POS, and start looking for the location of the arg1 from the POS of arg2.Posstr (arg1, arg2): returns the position where arg2 first appeared in arg1.Repeat (arg1, num_times): returns the string arg1 repeated num_times times.Replace (arg1, arg2, ARG3): replace all arg2 in arg1 to arg3.Right (Arg, length): returns a string consisting of lengthbytes on the left of the arg.Space (ARG): returns a string containing Arg spaces.Substr (arg1, POS, &lt, length>): returns the length character at the start of the POS position in arg1, and returns the remaining characters if no length is specified.4. Mathematical function:Abs, count, Max, min, sumCeil (ARG): returns the smallest integer greater than or equal to arg.Floor (ARG): returns the smallest integer less than or equal to the parameter.Mod (arg1,Arg2) returns arg1 by the remainder of the arg2, with the same symbol as arg1.Rand (): returns a random number between 1 and 1.Power (arg1, arg2): returns the arg2 power of arg1.Round (arg1, arg2): four, five into the truncated processing, arg2 is the number of bits, if arg2 is negative, then the number of decimal points before four to five processing.Sigh (ARG): symbolic designator to return arg. -1,0,1 representation.Truncate (arg1, arg2): truncate arg1, arg2 is the number of digits, and if arg2 is negative, keep the arg2 bits before the arg1 decimal point.5, others:Nullif (arg1, arg2): returns if the 2 arguments are equal, otherwise the argument 1 is returned。

经典SQL语句大全(超全)

经典SQL语句大全(超全)

一、基础1、说明:创建数据库CREATE DATABASE database-name2、说明:删除数据库drop database dbname3、说明:备份sql server--- 创建备份数据的 deviceUSE masterEXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1. dat'--- 开始备份BACKUP DATABASE pubs TO testBack4、说明:创建新表create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)根据已有的表创建新表:A:create table tab_new like tab_old (使用旧表创建新表)B:create table tab_new as select col1,col2… from tab_old definition only5、说明:删除新表drop table tabname6、说明:增加一个列Alter table tabname add column col type注:列增加后将不能删除。

DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。

7、说明:添加主键:Alter table tabname add primary key(col)说明:删除主键: Alter table tabname drop primary key(col)8、说明:创建索引:create [unique] index idxname on tabname(col….) 删除索引:drop index idxname注:索引是不可更改的,想更改必须删除重新建。

9、说明:创建视图:create view viewname as select statement删除视图:drop view viewname10、说明:几个简单的基本的sql语句选择:select * from table1 where 范围插入:insert into table1(field1,field2) values(value1,value2)删除:delete from table1 where 范围更新:update table1 set field1=value1 where 范围查找:select * from table1 where field1 like ’%value1%’ ---like的语法很精妙,查资料!排序:select * from table1 order by field1,field2 [desc]总数:select count as totalcount from table1求和:select sum(field1) as sumvalue from table1平均:select avg(field1) as avgvalue from table1最大:select max(field1) as maxvalue from table1最小:select min(field1) as minvalue from table111、说明:几个高级查询运算词A:UNION 运算符UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。

sql经典50题建表语句

sql经典50题建表语句

sql经典50题建表语句1、题目:创建一个名为"employees"的表,包含"id"、"name"和"salary"三个字段。

sql:CREATE TABLE employees (id INT PRIMARY KEY,name VARCHAR(50),salary DECIMAL(10, 2));2、题目:创建一个名为"orders"的表,包含"order_id"、"customer_id"和"order_date"三个字段。

sql:CREATE TABLE orders (order_id INT PRIMARY KEY,customer_id INT,order_date DATE);3、题目:创建一个名为"products"的表,包含"product_id"、"product_name"和"price"三个字段。

sql:CREATE TABLE products (product_id INT PRIMARY KEY,product_name VARCHAR(50),price DECIMAL(10, 2));4、题目:创建一个名为"customers"的表,包含"customer_id"、"first_name"、"last_name"和"email"四个字段。

sql:CREATE TABLE customers (customer_id INT PRIMARY KEY,first_name VARCHAR(50),last_name VARCHAR(50),email VARCHAR(100));5、题目:创建一个名为"addresses"的表,包含"address_id"、"street"、"city"和"state"四个字段。

常用sql查询语句大全

常用sql查询语句大全

常用sql查询语句大全常用SQL查询语句大全SQL (Structured Query Language) 是一种用于管理关系型数据库的编程语言,它可以用来从数据库中检索、插入、更新和删除数据。

以下是一些常用的SQL查询语句:1. SELECT语句:用于检索数据库中的数据。

- SELECT * FROM table_name; -- 检索表中的所有列和行- SELECT column1, column2 FROM table_name; -- 检索表中指定的列- SELECT column1, column2 FROM table_name WHERE condition; -- 检索满足条件的行2. INSERT语句:用于向数据库中插入新的数据。

- INSERT INTO table_name (column1, column2) VALUES (value1, value2); -- 插入指定的列和值- INSERT INTO table_name VALUES (value1, value2); -- 插入所有列和值3. UPDATE语句:用于更新数据库中的数据。

- UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition; -- 更新满足条件的行的值4. DELETE语句:用于从数据库中删除数据。

- DELETE FROM table_name WHERE condition; -- 删除满足条件的行5. WHERE子句:用于指定条件。

- SELECT * FROM table_name WHERE column_name = value; -- 检索满足条件的行- SELECT * FROM table_name WHERE column_name LIKE 'value%'; -- 使用通配符进行模糊匹配- SELECT * FROM table_name WHERE column_name IN (value1, value2); -- 检索列值在指定列表中的行6. ORDER BY子句:用于对结果进行排序。

数据库SQL经典语句

数据库SQL经典语句

数据库SQL经典语句1.创建表:CREATE TABLE table_namecolumn1 datatype constraint,column2 datatype constraint,...2.插入数据INSERT INTO table_name (column1, column2, ...) VALUES (value1, value2, ...);3.查询数据SELECT column1, column2, ...FROM table_nameWHERE conditionORDER BY columnLIMIT number;4.更新数据UPDATE table_nameSET column1 = value1, column2 = value2, ...WHERE condition;5.删除数据DELETE FROM table_nameWHERE condition;6.创建索引CREATE INDEX index_nameON table_name (column1, column2, ...);7.删除索引DROP INDEX index_name ON table_name;8.修改表结构ALTER TABLE table_nameADD column datatype constraint;9.删除表DROP TABLE table_name;10.聚合函数(求和、平均值、最大值、最小值等) SELECT aggregate_function(column)FROM table_nameWHERE conditionGROUP BY column;11.连接表FROM table1INNER JOIN table2 ON condition;12.子查询SELECT column1, column2, ...FROM table1WHERE column IN (SELECT column FROM table2 WHERE condition);13.内连接SELECT column1, column2, ...FROM table1JOIN table2 ON condition;14.外连接SELECT column1, column2, ...FROM table1LEFT JOIN table2 ON condition;SELECT column1, column2, ...FROM table1RIGHT JOIN table2 ON condition;15.独立查询FROM table1WHERE EXISTS (SELECT column FROM table2 WHERE condition);16.分组查询SELECT column1, aggregate_function(column2)FROM table_nameWHERE conditionGROUP BY column1;17.排名查询SELECT column1, column2, ..., RANK( OVER (ORDER BY column DESC)FROM table_name;以上是一些数据库SQL经典语句,覆盖了创建、插入、查询、更新、删除、索引、表结构修改、聚合函数、连接表、子查询、内连接、外连接、独立查询、分组查询、排名查询等常见的操作语言。

50个sql语句及讲解

50个sql语句及讲解

50个SQL语句及讲解1. SE LECT语句S E LE CT语句用于从数据库中选择数据。

S E LE CT*F RO M表名;该语句将返回表中的所有数据。

2. WH ERE语句W H ER E语句用于筛选满足指定条件的数据。

S E LE CT*F RO M表名W H ER E条件;可以使用比较运算符(如=、<、>)、逻辑运算符(如AN D、O R)以及通配符(如%、_)进行条件筛选。

3. OR DER BY语句O R DE RB Y语句用于对结果进行排序。

S E LE CT*F RO M表名O R DE RB Y列名A SC/D E SC;A S C表示升序排列,D E SC表示降序排列。

4. IN SERT INT O语句I N SE RT IN TO语句用于向数据库中插入新的数据。

I N SE RT IN TO表名(列1,列2,列3)V ALU E S(值1,值2,值3);将指定的数据插入到指定的列中。

5. UP DATE语句U P DA TE语句用于更新数据库中的数据。

U P DA TE表名SE T列名=新值WH ER E条件;更新满足条件的数据的指定列的值。

6. DE LETE语句D E LE TE语句用于从数据库中删除数据。

D E LE TE FR OM表名WH E RE条件;删除满足条件的数据。

7. LI KE语句L I KE语句用于在W HE R E语句中进行模糊匹配。

S E LE CT*F RO M表名W H ER E列名L IK E'ab c%';以匹配指定模式的数据。

8. DI STINCT语句D I ST IN CT语句用于返回唯一不重复的数据。

S E LE CT DI ST IN CT列名F RO M表名;返回指定列中的不重复数据。

9. GR OUP BY语句G R OU PB Y语句用于按照指定列对数据进行分组。

S E LE CT列1,C OU NT(列2)FR OM表名GRO U PB Y列1;按列1的值分组,并计算每组中列2的数量。

SQL的基本查询语句大全

SQL的基本查询语句大全

SQL(结构化查询语言)是用于管理关系数据库系统的标准语言。

以下是一些基本的SQL查询语句的示例:1. **选择所有列**```sqlSELECT * FROM 表名;```2. **选择特定列**```sqlSELECT 列名1, 列名2 FROM 表名;```3. **添加条件**```sqlSELECT * FROM 表名WHERE 条件;```4. **排序结果**```sqlSELECT * FROM 表名ORDER BY 列名ASC/DESC;```5. **插入数据**```sqlINSERT INTO 表名(列名1, 列名2, ...) VALUES (值1, 值2, ...);```6. **更新数据**```sqlUPDATE 表名SET 列名1 = 值1, 列名2 = 值2, ... WHERE 条件; ```7. **删除数据**```sqlDELETE FROM 表名WHERE 条件;```8. **连接表**```sqlSELECT * FROM 表名1 JOIN 表名2 ON 表名1.列名= 表名2.列名; ```9. **聚合函数**```sqlSELECT COUNT(列名) FROM 表名WHERE 条件; --计数SELECT SUM(列名) FROM 表名WHERE 条件; --求和SELECT AVG(列名) FROM 表名WHERE 条件; --平均值SELECT MAX(列名) FROM 表名WHERE 条件; --最大值SELECT MIN(列名) FROM 表名WHERE 条件; --最小值```10. **分组和筛选**```sqlSELECT 列名, COUNT(*) FROM 表名GROUP BY 列名HAVING COUNT(*) > 值; --分组和筛选聚合数据```11. **子查询**```sqlSELECT * FROM 表名WHERE 列名IN (SELECT 列名FROM 表名WHERE 条件); -- IN 子查询SELECT * FROM 表名WHERE 列名= (SELECT 列名FROM 表名WHERE 条件); -- = 子查询(通常用于单行子查询)```12. **插入多行数据** (在某些数据库中可能不支持)```sqlINSERT INTO 表名(列名1, 列名2, ...) VALUES (值1a, 值2a, ...), (值1b, 值2b, ...), ...;```请注意,上述SQL语句仅为基本示例,实际使用时可能需要根据具体的数据库系统和需求进行调整。

数据库sql语句大全实例

数据库sql语句大全实例

数据库sql语句大全实例以下是一些常见的数据库SQL语句实例:1. 创建表:CREATE TABLE 表名 (列1 数据类型,列2 数据类型,...);例如:CREATE TABLE students (id INT,name VARCHAR(50),age INT);2. 插入数据:INSERT INTO 表名 (列1, 列2, ...) VALUES (值1, 值2, ...);例如:INSERT INTO students (id, name, age) VALUES (1, 'Alice', 20);INSERT INTO students (id, name, age) VALUES (2, 'Bob', 22);3. 查询数据:SELECT 列1, 列2, ... FROM 表名 WHERE 条件;例如:SELECT * FROM students;SELECT name, age FROM students WHERE age > 20;4. 更新数据:UPDATE 表名 SET 列 = 值 WHERE 条件;例如:UPDATE students SET age = 21 WHERE name = 'Alice';5. 删除数据:DELETE FROM 表名 WHERE 条件;例如:DELETE FROM students WHERE age < 22;6. 创建索引:CREATE INDEX 索引名 ON 表名 (列1, 列2, ...);例如:CREATE INDEX idx_students_age ON students (age);7. 删除索引:DROP INDEX 索引名 ON 表名;例如:DROP INDEX idx_students_age ON students;以上是一些常见的数据库SQL语句实例,具体使用时需要根据具体的数据库类型和表结构进行调整。

(word完整版)数据库SQL经典语句(包含几乎所有的经典操作语言)

(word完整版)数据库SQL经典语句(包含几乎所有的经典操作语言)

1、说明:复制表(只复制结构,源表名:a 新表名:b)(Access可用)法一:select * into b from a where 1〈〉1法二:select top 0 * into b from a2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用)insert into b(a, b, c) select d,e,f from b;3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用)insert into b(a, b, c) select d,e,f from b in ‘具体数据库' where 条件例子:。

.from b in ’”&Server.MapPath(”。

”)&”\data.mdb” &"’ where.。

4、说明:子查询(表名1:a 表名2:b)select a,b,c from a where a IN (select d from b )或者: select a,b,c from a where a IN (1,2,3)5、说明:显示文章、提交人和最后回复时间select a.title,a。

username,b。

adddate from table a,(select max(adddate) adddate from table where table。

title=a。

title) b6、说明:外连接查询(表名1:a 表名2:b)select a.a, a.b, a。

c, b。

c, b.d, b。

f from a LEFT OUT JOIN b ON a.a = b.c7、说明:在线视图查询(表名1:a )select * from (SELECT a,b,c FROM a) T where t.a 〉 1;8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括select * from table1 where time between time1 and time2select a,b,c, from table1 where a not between 数值1 and 数值29、说明:in 的使用方法select * from table1 where a [not] in (‘值1',’值2',’值4',’值6’)10、说明:两张关联表,删除主表中已经在副表中没有的信息delete from table1 where not exists ( select * from table2 where table1.field1=table2。

SQL查询语句大全

SQL查询语句大全

SQL查询语句大全1. SELECT语句1.1 查询单表数据SELECT column1, column2, ... FROM table_name;1.2 查询多表数据SELECT column1, column2, ... FROM table1JOIN table2 ON condition;1.3 使用WHERE子句过滤数据SELECT column1, column2, ... FROM table_nameWHERE condition;1.4 使用ORDER BY子句排序结果SELECT column1, column2, ... FROM table_nameORDER BY column_name [ASC|DESC];1.5 使用LIMIT子句限制结果条数SELECT column1, column2, ...FROM table_nameLIMIT number;2. INSERT语句2.1 插入单条数据INSERT INTO table_name (column1, column2, ...) VALUES (value1, value2, ...);2.2 插入多条数据INSERT INTO table_name (column1, column2, ...) VALUES(value1, value2, ...),(value1, value2, ...),...;3. UPDATE语句3.1 更新单条数据UPDATE table_nameSET column1 = value1, column2 = value2, ... WHERE condition;3.2 更新多条数据UPDATE table_nameSET column1 = value1, column2 = value2, ... WHERE condition;4. DELETE语句4.1 删除单条数据DELETE FROM table_nameWHERE condition;4.2 删除多条数据DELETE FROM table_nameWHERE condition;5. GROUP BY语句5.1 分组并计算汇总数据SELECT column1, aggregate_function(column2) FROM table_nameGROUP BY column1;5.2 过滤分组结果SELECT column1, aggregate_function(column2) FROM table_nameGROUP BY column1HAVING condition;6. JOIN语句6.1 INNER JOINSELECT column1, column2, ...FROM table1INNER JOIN table2 ON condition;6.2 LEFT JOINSELECT column1, column2, ...FROM table1LEFT JOIN table2 ON condition;6.3 RIGHT JOINSELECT column1, column2, ...FROM table1RIGHT JOIN table2 ON condition;6.4 FULL JOINSELECT column1, column2, ... FROM table1FULL JOIN table2 ON condition;7. UNION语句7.1 使用UNION合并查询结果(SELECT column1, column2, ... FROM table1)UNION(SELECT column1, column2, ... FROM table2);7.2 使用UNION ALL合并查询结果(SELECT column1, column2, ... FROM table1)UNION ALL(SELECT column1, column2, ... FROM table2);8. 子查询语句8.1 单行子查询SELECT column1, column2, ... FROM table_nameWHERE column1 = (SELECT column2 FROM table2 WHERE condition);8.2 多行子查询SELECT column1, column2, ...FROM table_nameWHERE column1 IN (SELECT column2 FROM table2 WHERE condition);9. CASE语句9.1 简单CASE语句SELECT column1,CASE column2WHEN'value1'THEN'result1'WHEN'value2'THEN'result2'ELSE'result3'ENDFROM table_name;9.2 搜索CASE语句SELECT column1,CASEWHEN condition1 THEN'result1'WHEN condition2 THEN'result2'ELSE'result3'ENDFROM table_name;以上是一些常见的SQL查询语句,希望对你的工作有所帮助。

基础sql语句汇总

基础sql语句汇总

基础sql语句(1)数据记录筛选:#sql="select * from 数据表where 字段名=字段值order by 字段名"sql="select * from 数据表where 字段名like ‘%字段值%‘ order by 字段名"sql="select top 10 * from 数据表where 字段名order by 字段名"sql="select * from 数据表where 字段名in (‘值1‘,‘值2‘,‘值3‘)"sql="select * from 数据表where 字段名between 值1 and 值2"(2) 更新数据记录:sql="update 数据表set 字段名=字段值where 条件表达式"sql="update 数据表set 字段1=值1,字段2=值2 …… 字段n=值n where 条件表达式"(3) 删除数据记录:sql="delete from 数据表where 条件表达式"sql="delete from 数据表" (将数据表所有记录删除)(4) 添加数据记录:sql="insert into 数据表(字段1,字段2,字段3 …) valuess (值1,值2,值3 …)"sql="insert into 目标数据表select * from 源数据表" (把源数据表的记录添加到目标数据表)(5) 数据记录统计函数:AVG(字段名) 得出一个表格栏平均值COUNT(*|字段名) 对数据行数的统计或对某一栏有值的数据行数统计MAX(字段名) 取得一个表格栏最大的值MIN(字段名) 取得一个表格栏最小的值SUM(字段名) 把数据栏的值相加引用以上函数的方法:sql="select sum(字段名) as 别名from 数据表where 条件表达式"set rs=conn.excute(sql)用rs("别名") 获取统的计值,其它函数运用同上。

常用sql查询语句大全

常用sql查询语句大全

常用sql查询语句大全以下是SQL中常用的查询语句:1. SELECT语句:选择表中的数据。

```SELECT column1, column2, column3FROM table_nameWHERE conditionORDER BY column_name DESC, column_name ASC```上面的查询语句将选择名为“column1”、“column2”和“column3”的表中的所有数据,并按照“column_name”的升序和降序进行排序。

2. INSERT INTO语句:将数据插入到表中。

```INSERT INTO table_name (column1, column2, column3)VALUES (value1, value2, value3)```上面的查询语句将创建一个名为“table_name”的表,该表包含三个字段,分别为“column1”、“column2”和“column3”,并插入三条数据,分别为“value1”、“value2”和“value3”。

3. UPDATE语句:更新表中的数据。

```UPDATE table_nameSET column1 = value1, column2 = value2, column3 = value3 WHERE condition```上面的查询语句将根据给定的“condition”更新名为“table_name”的表中的“column1”、“column2”和“column3”三个字段中的数据,并将结果输出到查询结果中。

4. DELETE语句:删除表中的数据。

```DELETE FROM table_nameWHERE condition```上面的查询语句将根据给定的“condition”从名为“table_name”的表中删除所有数据。

数据库查询sql语句大全

数据库查询sql语句大全

数据库查询sql语句大全一、常用查询语句1. SELECT:查询语句,用于从表中选取数据。

2. FROM:指定要查询的表名称。

4. ORDER BY:将结果集按照指定的列进行排序。

二、数据过滤语句1. WHERESELECT * FROM 表名 WHERE 列名=值; --- 查找指定值SELECT * FROM 表名 WHERE 列名<>值; --- 不等于指定值SELECT * FROM 表名 WHERE 列名>值; --- 大于指定值SELECT * FROM 表名 WHERE 列名>=值; --- 大于等于指定值SELECT * FROM 表名 WHERE 列名<值; --- 小于指定值SELECT * FROM 表名 WHERE 列名<=值; --- 小于等于指定值SELECT * FROM 表名 WHERE 列名 BETWEEN 值1 AND 值2; --- 查找指定范围内的值SELECT * FROM 表名 WHERE 列名 LIKE '值%'; --- 查找以指定值开头的值SELECT * FROM 表名 WHERE 列名 LIKE '%值'; --- 查找以指定值结尾的值SELECT * FROM 表名 WHERE 列名 LIKE '%值%'; --- 查找包含指定值的值2. INSELECT * FROM 表名 WHERE 列名 IN (值1,值2,...); --- 查找在指定值列表中的值3. NOT IN4. EXISTS6. LIKE三、运算符1. 加法 +SELECT 列名1 + 列名2 AS 别名 FROM 表名;2. 减法 -3. 乘法 *4. 除法 /5. 取模 %四、数据排序1. ORDER BYSELECT * FROM 表名 ORDER BY 列名 ASC; --- 升序排序SELECT * FROM 表名 ORDER BY 列名 DESC; --- 降序排序2. 多列排序五、数据聚合1. COUNT2. SUM3. AVG4. MAX六、数据分组SELECT 列名1,COUNT(列名2) AS 别名 FROM 表名 GROUP BY 列名1; --- 按照列名1分组,计算列名2的计数七、数据连接1. 内连接SELECT * FROM 表1 INNER JOIN 表2 ON 条件; --- 内连接表1和表2,并按照条件进行匹配八、数据更新和删除1. UPDATE2. DELETEDELETE FROM 表名 WHERE 条件; --- 删除表中满足条件的记录1. CREATE TABLEDROP TABLE 表名; --- 删除表十、数据备份和还原1. 备份mysqldump -u用户名 -p密码数据库名 > 备份文件.sql;2. 还原以上就是数据库查询SQL语句大全中文部分了。

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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括
select * from table1 where time between time1 and time2
select a,b,c, from table1 where a not between 数值1 and 数值2
法一:select * into b from a where 1<>1
法二:select top 0 * into b from a
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用)
insert into b(a, b, c) select d,e,f from b;
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用)
insert into b(a, b, c) select d,e,f from b in ‘具体数据库’ where 条件
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..
B:right outer join:
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。
C:full outer join:
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。
其次,大家来看一些不错的sql语句
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
删除视图:drop view viewname
10、说明:几个简单的基本的sql语句
选择:select * from table1 where 范围
插入:insert into table1(field1,field2) values(value1,value2)
删除:delete from table1 where 范围
最小:select min(field1) as minvalue from table1
11、说明:几个高级查询运算词
A: UNION 运算符
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。
数据库对象 说明
表 由行和列构成的集合,用了存储数据
数据类型 定义列或变量的数据类型,SQL Server提供了系统数据类型,并允许用户自定义数据类型
视图 由表或其他视图导出的虚拟表
索引 为数据快速检索提供支持,且可以保证数据唯一性的辅助数据结构
约束 用于为表中的列定义完整性的规则
总数:select count * as totalcount from table1
求和:select sum(field1) as sumvalue from table1
平均:select avg(field1) as avgvalue from table1
最大:select max(field1) as maxvalue from table1
9、说明:in 的使用方法
select * from table1 where a [not] in (‘值1’,’值2’,’值4’,’值6’)
10、说明:两张关联表,删除主表中已经在副表中没有的信息
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )
4、说明:创建新表
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)
根据已有的表创建新表:
A:create table tab_new like tab_old (使用旧表创建新表)
3、说明:备份sql server
--- 创建 备份数据的 device
USE master
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat'
--- 开始 备份
BACKUP DATABASE pubs TO testBack
注:使用运算词的几个查询结果行必须是一致的。
12、说明:使用外连接
A、left outer join:
左外连பைடு நூலகம்(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
20、说明:列出数据库里所有的表名
select name from sysobjects where type='U'
21、说明:列出表里的所有的
select name from syscolumns where id=object_id('TableName')
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。
13、说明:一条sql 语句搞定数据库分页
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段
14、说明:前10条记录
默认值 为列提供的默认值
存储过程 存放于服务器的预先编译好的一组T-SQL语句
触发器 特殊的存储过程,当用户表中的数据发生改变时,该存储过程自动执行
首先,简要介绍基础语句:
1、说明:创建数据库
CREATE DATABASE database-name
2、说明:删除数据库
drop database dbname
11、说明:四表联查问题:
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where .....
12、说明:日程安排提前五分钟提醒
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。
7、说明:添加主键: Alter table tabname add primary key(col)
说明:删除主键: Alter table tabname drop primary key(col)
8、说明:创建索引:create [unique] index idxname on tabname(col….)
删除索引:drop index idxname
注:索引是不可更改的,想更改必须删除重新建。
9、说明:创建视图:create view viewname as select statement
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type
SQL系统的一些数据库
数据库 描述
master 对用户数据库和SQL Server的操作进行总体的控制
model 提供创建新用户数据库所需的模板和原型
tempdb 提供临时表和其他临时工作存储量所需的存储区
msdb 提供调度信息和作业历史记录所需的存储区
SQL常用数据库对象
更新:update table1 set field1=value1 where 范围
查找:select * from table1 where field1 like ’%value1%’ ---like的语法很精妙,查资料!
排序:select * from table1 order by field1,field2 [desc]
下列语句部分是MsSql语句,不可以在access中使用。和原文相比,我加入了一些常用的内容
SQL分类:
DDL—数据定义语言(CREATE,ALTER,DROP,DECLARE)
DML—数据操纵语言(SELECT,DELETE,UPDATE,INSERT)
DCL—数据控制语言(GRANT,REVOKE,COMMIT,ROLLBACK)
select top 10 * form table1 where 范围
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.)
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