SQL基础知识V2——SQL语句快速参考

AND / OR  并且/或  

SELECT column_name(s)
FROM table_name
WHERE condition
AND|OR condition


ALTER TABLE  修改表

ALTER TABLE table_name
ADD column_name datatype
--或
ALTER TABLE table_name
DROP COLUMN column_name


AS (alias)  重命名

--对列名进行重命名
SELECT column_name AS column_alias
FROM table_name
--对表名进行重命名
SELECT column_name
FROM table_name  AS table_alias

BETWEEN...AND...  在某个区间

SELECT column_name(s)
FROM table_name
WHERE column_name
BETWEEN value1 AND value2


CREATE DATABASE   创建数据库

CREATE DATABASE database_name


CREATE TABLE  创建表

CREATE TABLE table_name
(
column_name1 data_type,
column_name2 data_type,
column_name2 data_type,
...
)


CREATE INDEX   创建索引

--创建普通索引
CREATE INDEX index_name
ON table_name (column_name)
--创建唯一索引
CREATE UNIQUE INDEX index_name
ON table_name (column_name)


CREATE VIEW   创建视图

CREATE VIEW view_name AS
SELECT column_name(s)
FROM table_name
WHERE condition


DELETE  删除

--带条件的删除
DELETE FROM table_name
WHERE some_column=some_value
--不带条件的删除
DELETE FROM table_name


DROP DATABASE  删除数据库

DROP DATABASE database_name


DROP INDEX  删除索引

--SQL Server的写法
DROP INDEX table_name.index_name
--DB2/Oracle的写法
DROP INDEX index_name
--Mysql的写法
ALTER TABLE table_name
DROP INDEX index_name


DROP TABLE  删除表

DROP TABLE table_name


GROUP BY   分组

SELECT column_name, aggregate_function(column_name)
FROM table_name
WHERE column_name operator value
GROUP BY column_name


HAVING   分组过滤条件

SELECT column_name, aggregate_function(column_name)
FROM table_name
WHERE column_name operator value
GROUP BY column_name
HAVING aggregate_function(column_name) operator value


IN  在某些固定值中查找

SELECT column_name(s)
FROM table_name
WHERE column_name
IN (value1,value2,..)


INSERT INTO  插入表

INSERT INTO table_name
VALUES (value1, value2, value3,....)
--或
INSERT INTO table_name
(column1, column2, column3,...)
VALUES (value1, value2, value3,....)


INNER JOIN  内连接

SELECT column_name(s)
FROM table_name1
INNER JOIN table_name2
ON table_name1.column_name=table_name2.column_name


LEFT JOIN  左连接

SELECT column_name(s)
FROM table_name1
LEFT JOIN table_name2
ON table_name1.column_name=table_name2.column_name


RIGHT JOIN  右连接

SELECT column_name(s)
FROM table_name1
RIGHT JOIN table_name2
ON table_name1.column_name=table_name2.column_name


FULL JOIN  全连接

SELECT column_name(s)
FROM table_name1
FULL JOIN table_name2
ON table_name1.column_name=table_name2.column_name


LIKE  模糊匹配

SELECT column_name(s)
FROM table_name
WHERE column_nameLIKE pattern


ORDER BY  排序

SELECT column_name(s)
FROM table_name
ORDER BY column_name [ASC|DESC]


SELECT  查找

SELECT column_name(s)
FROM table_name


SELECT *  查找表的所有字段

SELECT *
FROM table_name


SELECT DISTINCT  查找去除重复的列

SELECT DISTINCT column_name(s)
FROM table_name


SELECT INTO  查询结果插入表

SELECT *
INTO new_table_name [IN externaldatabase]
FROM old_table_name
--或
SELECT column_name(s)
INTO new_table_name [IN externaldatabase]
FROM old_table_name


SELECT TOP  查询前N条记录

SELECT TOP number|percent column_name(s)
FROM table_name


TRUNCATE TABLE  清空表

TRUNCATE TABLE table_name


UNION  去重并集

SELECT column_name(s) FROM table_name1
UNION
SELECT column_name(s) FROM table_name2


UNION ALL  不去重并集

SELECT column_name(s) FROM table_name1
UNION ALL
SELECT column_name(s) FROM table_name2


UPDATE  更新

UPDATE table_name
SET column1=value, column2=value,...
WHERE some_column=some_value


WHERE   条件过滤

SELECT column_name(s)
FROM table_name
WHERE column_name operator value


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