选择具有相同ID但MySQL中对应记录不同的值的计数（是，否）？
为此，您可以SUM()与CASE语句一起使用。让我们首先创建一个-
mysql> create table DemoTable1430
-> (
-> EmployeeId int,
-> isMarried ENUM('YES','NO')
-> );使用insert在表中插入一些记录-
mysql> insert into DemoTable1430 values(1001,'Yes'); mysql> insert into DemoTable1430 values(1001,'No'); mysql> insert into DemoTable1430 values(1001,'Yes'); mysql> insert into DemoTable1430 values(1001,'Yes');
使用选择显示表中的所有记录-
mysql> select * from DemoTable1430;
这将产生以下输出-
+------------+-----------+ | EmployeeId | isMarried | +------------+-----------+ | 1001 | YES | | 1001 | NO | | 1001 | YES | | 1001 | YES | +------------+-----------+ 4 rows in set (0.00 sec)
这是选择值计数的查询（是，否）-
mysql> select EmployeeId,sum(isMarried='Yes') as NumberOfMarried, -> sum(isMarried='No') as NumberOfUnMarried -> from DemoTable1430 -> group by EmployeeId;
这将产生以下输出-
+------------+-----------------+-------------------+ | EmployeeId | NumberOfMarried | NumberOfUnMarried | +------------+-----------------+-------------------+ | 1001 | 3 | 1 | +------------+-----------------+-------------------+ 1 row in set (0.00 sec)
热门推荐
10 财运虎年祝福语简短语
11 单亲爸爸春节祝福语简短
12 狗狗上厕所训练
13 植物种植祝福语简短
14 翻译考试祝福语朋友简短
15 个人周年庆简短祝福语
16 狗狗怎么训练
17 分别祝福语简短搞笑英文
18 生日广州男生祝福语简短