mysql表中数据修改操作:
执行:UPDATE test SET age = age -5 WHERE id = 0;
//id=0的 age减少5 所以从30变为了25;
mysql表中数据删除操作:
DELETE FROM test WHERE id = 5;
对查询结果进行分组:
SELECT password From test GROUP BY password;
HAVING是分组条件。
HAVING的用法:
SELECT password,age From test GROUP BY password HAVING age>30;
mysql对查询结果进行排序:
ASC升序排列,DESC降序排列。
限制记录返回的数量:
LIMIT关键字
SELECT * FROM test LIMIT 2;
SELECT * FROM test LIMIT 3,2;
从第三条开始返回两条