MySQL 查询选择列值仅为 0 的行，按另一列分组?
mysqlmysqli database更新于 2024/3/15 6:59:00
为此，使用 group by。让我们首先创建一个表 −
mysql> create table DemoTable1344 -> ( -> `SequenceId` int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ClientId int, -> isMarried tinyint(1) -> ); Query OK, 0 rows affected (0.49 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable1344(ClientId,isMarried) values(4567,0); Query OK, 1 row affected (0.45 sec) mysql> insert into DemoTable1344(ClientId,isMarried) values(9876,0); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1344(ClientId,isMarried) values(5432,1); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1344(ClientId,isMarried) values(4567,1); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable1344(ClientId,isMarried) values(9873,0); Query OK, 1 row affected (0.15 sec)
使用 select 语句显示表中的所有记录 −
mysql> select * from DemoTable1344;
这将产生以下输出 −
+------------+----------+-----------+ | SequenceId | ClientId | isMarried | +------------+----------+-----------+ | 1 | 4567 | 0 | | 2 | 9876 | 0 | | 3 | 5432 | 1 | | 4 | 4567 | 1 | | 5 | 9873 | 0 | +------------+----------+-----------+ 5 rows in set (0.00 sec)
以下查询用于选择列值仅为 0 的行，并按另一列进行分组 −
mysql> select SequenceId,ClientId,isMarried -> from DemoTable1344 -> group by ClientId -> having isMarried=0;
这将产生以下输出 −
+------------+----------+-----------+ | SequenceId | ClientId | isMarried | +------------+----------+-----------+ | 1 | 4567 | 0 | | 2 | 9876 | 0 | | 5 | 9873 | 0 | +------------+----------+-----------+ 3 rows in set (0.00 sec)
