SQL基础知识普及(十四)——语句快速参考

以下是一些可以当工具书使用的参考语句~

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

or

ALTER TABLE table_name
DROP COLUMN column_name

AS (alias)  重命名

SELECT column_name AS column_alias
FROM table_name

or

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

CREATE INDEX index_name
ON table_name (column_name)

or

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

DELETE FROM table_name
WHERE some_column=some_value

or

DELETE FROM table_name
(Note: Deletes the entire table!!)

DELETE * FROM table_name
(Note: Deletes the entire table!!)

DROP DATABASE  删除数据库

DROP DATABASE database_name    

DROP INDEX  删除索引

DROP INDEX table_name.index_name (SQL Server)
DROP INDEX index_name ON table_name (MS Access)
DROP INDEX index_name (DB2/Oracle)
ALTER TABLE table_name
DROP INDEX index_name (MySQL)

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,....)

or

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

or

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