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SQL 教程

SQL主页 SQL简介 SQL语法 SQL选择 SQL选择 Distinct SQL位置 SQL运算符 SQL排序依据 SQL插入 SQL空值 SQL更新 SQL删除 SQL选择 Top SQL最小和最大 SQL计数 SQL喜爱 SQL通配符 SQL输入 SQL之间 SQL别名 SQL连接 SQL输入ner Join SQL左联接 SQL右连接 SQL完全联接 SQL自连接 SQL联盟 SQL分组依据 SQL具有 SQL存在 SQL全部 SQL选择 Into SQL插入 Select SQL案例 SQL空函数 SQL存储过程 SQL注释 SQL运算符

SQL 数据库

SQL创建数据库 SQL Drop DB SQL备份数据库 SQL创建表 SQL删除表 SQL变更表 SQL约束 SQL不为空 SQL唯一 SQL主键 SQL外键 SQL检查 SQL默认值 SQL输入dex SQL自动增量 SQL日期 SQL视图 SQL输入jection SQL托管 SQL数据类型

SQL 参考

SQL关键字
ADD ADD CONSTRAINT ALTER ALTER COLUMN ALTER TABLE ALL AND ANY AS ASC BACKUP DATABASE BETWEEN CASE CHECK COLUMN CONSTRAINT CREATE CREATE DATABASE CREATE INDEX CREATE OR REPLACE VIEW CREATE TABLE CREATE PROCEDURE CREATE UNIQUE INDEX CREATE VIEW DATABASE DEFAULT DELETE DESC DISTINCT DROP DROP COLUMN DROP CONSTRAINT DROP DATABASE DROP DEFAULT DROP INDEX DROP TABLE DROP VIEW EXEC EXISTS FOREIGN KEY FROM FULL OUTER JOIN GROUP BY HAVING IN INDEX INNER JOIN INSERT INTO INSERT INTO SELECT IS NULL IS NOT NULL JOIN LEFT JOIN LIKE LIMIT NOT NOT NULL OR ORDER BY OUTER JOIN PRIMARY KEY PROCEDURE RIGHT JOIN ROWNUM SELECT SELECT DISTINCT SELECT INTO SELECT TOP SET TABLE TOP TRUNCATE TABLE UNION UNION ALL UNIQUE UPDATE VALUES VIEW WHERE
MySQL函数
字符串函数 ASCII CHAR_LENGTH CHARACTER_LENGTH CONCAT CONCAT_WS FIELD FIND_IN_SET FORMAT INSERT INSTR LCASE LEFT LENGTH LOCATE LOWER LPAD LTRIM MID POSITION REPEAT REPLACE REVERSE RIGHT RPAD RTRIM SPACE STRCMP SUBSTR SUBSTRING SUBSTRING_INDEX TRIM UCASE UPPER 数值函数 ABS ACOS ASIN ATAN ATAN2 AVG CEIL CEILING COS COT COUNT DEGREES DIV EXP FLOOR GREATEST LEAST LN LOG LOG10 LOG2 MAX MIN MOD PI POW POWER RADIANS RAND ROUND SIGN SIN SQRT SUM TAN TRUNCATE 日期功能 ADDDATE ADDTIME CURDATE CURRENT_DATE CURRENT_TIME CURRENT_TIMESTAMP CURTIME DATE DATEDIFF DATE_ADD DATE_FORMAT DATE_SUB DAY DAYNAME DAYOFMONTH DAYOFWEEK DAYOFYEAR EXTRACT FROM_DAYS HOUR LAST_DAY LOCALTIME LOCALTIMESTAMP MAKEDATE MAKETIME MICROSECOND MINUTE MONTH MONTHNAME NOW PERIOD_ADD PERIOD_DIFF QUARTER SECOND SEC_TO_TIME STR_TO_DATE SUBDATE SUBTIME SYSDATE TIME TIME_FORMAT TIME_TO_SEC TIMEDIFF TIMESTAMP TO_DAYS WEEK WEEKDAY WEEKOFYEAR YEAR YEARWEEK 进阶功能 BIN BINARY CASE CAST COALESCE CONNECTION_ID CONV CONVERT CURRENT_USER DATABASE IF IFNULL ISNULL LAST_INSERT_ID NULLIF SESSION_USER SYSTEM_USER USER VERSION
SQL Server函数
字符串函数 ASCII CHAR CHARINDEX CONCAT Concat with + CONCAT_WS DATALENGTH DIFFERENCE FORMAT LEFT LEN LOWER LTRIM NCHAR PATINDEX QUOTENAME REPLACE REPLICATE REVERSE RIGHT RTRIM SOUNDEX SPACE STR STUFF SUBSTRING TRANSLATE TRIM UNICODE UPPER 数值函数 ABS ACOS ASIN ATAN ATN2 AVG CEILING COUNT COS COT DEGREES EXP FLOOR LOG LOG10 MAX MIN PI POWER RADIANS RAND ROUND SIGN SIN SQRT SQUARE SUM TAN 日期功能 CURRENT_TIMESTAMP DATEADD DATEDIFF DATEFROMPARTS DATENAME DATEPART DAY GETDATE GETUTCDATE ISDATE MONTH SYSDATETIME YEAR 进阶功能 CAST COALESCE CONVERT CURRENT_USER IIF ISNULL ISNUMERIC NULLIF SESSION_USER SESSIONPROPERTY SYSTEM_USER USER_NAME
MS Access功能
字符串函数 Asc Chr Concat with & CurDir Format InStr InstrRev LCase Left Len LTrim Mid Replace Right RTrim Space Split Str StrComp StrConv StrReverse Trim UCase 数值函数 Abs Atn Avg Cos Count Exp Fix Format Int Max Min Randomize Rnd Round Sgn Sqr Sum Val 日期功能 Date DateAdd DateDiff DatePart DateSerial DateValue Day Format Hour Minute Month MonthName Now Second Time TimeSerial TimeValue Weekday WeekdayName Year 其他功能 CurrentUser Environ IsDate IsNull IsNumeric
SQL快速参考

SQL 示例

SQL 示例 SQL测验 SQL 练习 SQL证书

SQL Tutorial

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SQL is a standard language for storing, manipulating and retrieving data in databases.

Our SQL tutorial will teach you how to use SQL in: MySQL, SQL Server, MS Access, Oracle, Sybase, Informix, Postgres, and other database systems.

Start learning SQL now »

示例 in Each Chapter

With our online SQL editor, you can edit the SQL statements, and click on a button to view the result.

Example

SELECT * FROM Customers;
来试试吧 »

Click on the "来试试吧" button to see how it works.

SQL 练习

Test Yourself With 练习

Exercise:

Insert the missing statement to get all the columns from the Customers table.

 * FROM Customers;

Start the Exercise

SQL 示例

Learn by examples! This tutorial supplements all explanations with clarifying examples.

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SQL 参考

At W3Schools you will find a complete reference for keywords and function:

SQL Keyword 参考

MYSQL Functions

SQLServer Functions

MS Access功能

SQL快速参考erence

SQL数据类型

Data types and ranges for Microsoft Access, MySQL and SQL Server.

SQL数据类型


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