如何在 MySQL 中返回具有相同列值的行?
mysqlmysqli database更新于 2025/9/11 8:12:17
为此使用 GROUP BY 子句。让我们首先创建一个表 −
mysql> create table DemoTable -> ( -> StudentId int, -> StudentMarks int -> ); Query OK, 0 rows affected (4.71 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable values(23,58); Query OK, 1 row affected (0.70 sec) mysql> insert into DemoTable values(25,89); Query OK, 1 row affected (0.46 sec) mysql> insert into DemoTable values(26,58); Query OK, 1 row affected (1.13 sec) mysql> insert into DemoTable values(28,98); Query OK, 1 row affected (0.86 sec)
使用 select 语句显示表中的所有记录 −
mysql> select *from DemoTable;
输出
+-----------+--------------+ | StudentId | StudentMarks | +-----------+--------------+ | 23 | 58 | | 25 | 89 | | 26 | 58 | | 28 | 98 | +-----------+--------------+ 4 rows in set (0.00 sec)
以下查询用于返回 MySQL 中具有相同列值的行 −
mysql> select StudentMarks from DemoTable -> group by StudentMarks -> having sum(StudentId=23) > 0 and -> sum(StudentId=26) > 0;
输出
+--------------+ | StudentMarks | +--------------+ | 58 | +--------------+ 1 row in set (0.00 sec)
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mysql 参考教程 - 该教程包含有关 mysql 的更多信息:https://www.cainiaomax.com/mysql/

