mysql数据库查询

查询表xiang

SELECT * FROM xiang

查询表xiang 的id，name列

SELECT id，name FROM xiang

查询name 列的重复值

SELECT DISTINCT name FROM xiang

提取表里指定的值

SELECT * FROM xiang WHERE NAME='xiangdingjun' ;

满足两个条件范围查询and

SELECT * FROM xiang WHERE id >5 and id <10 ;

满足其中一个条件查询 or

SELECT * FROM xiang WHERE id>1 or id>2;

满足不包括这条件

SELECT * FROM xiang WHERE NOT id<5;

查询name中的null 空值

SELECT * FROM xiang WHERE name is null;

SELECT count(*) FROM xiang /统计行为null的值

查询200 到 1000的中间值

SELECT * FROM xiang WHERE id BETWEEN 200 and 1000;

多个条件查询

SELECT * FROM xiang WHERE id IN(100,200,300);

模糊查询

SELECT * FROM xiang WHERE name LIKE ('M%') 查询字节前面含有M的值

M% 第一个字节含有M的值

%M% 查询值中含有M的值

%M 末尾含有M的值

_M% 查询第二个字节含有M的值

查询name中含有 xiang的值且id >50的值

SELECT * FROM xiang WHERE name = 'xiang' AND id >50;

SELECT * FROM xiang

WHERE id > 15

AND ( name = 'xiangdingjun' OR name = 'xiangge');

多列查询

SELECT * FROM xiang

ORDER BY id,name;

多表查询

select 字段1, 字段2 .from表1, 表2 [where条件]