数据库多表查询及嵌套查询子查询语句示例

简单数据库但表查询select*fromkjbdsjkwhere姓名=王勇and分数=87groupby课程orderby分数1.利用FROM子句进行多表查询:selectkjbdsjk.编号,kjbdsjk.姓名,kjbdsjk.职业,duobiao.收入fromkjbdsjk,duobiaowherekjbdsjk.编号=duobiao.编号andduobiao.收入>30002.合并多个结果集:select编号,姓名,年龄fromkjbdsjkunionselect编号,姓名,年龄fromshuzcx说明UNION运算符合并多个结果集.3.简单嵌套查询:sel