如何在其自己的MySQL查询中获取值的总出现次数？
为此，您可以使用子查询。让我们首先创建一个表-
create table DemoTable -> ( -> Value int -> );
使用插入命令在表中插入一些记录-
insert into DemoTable values(20); insert into DemoTable values(30); insert into DemoTable values(20); insert into DemoTable values(40); insert into DemoTable values(30); insert into DemoTable values(20);
使用select语句显示表中的所有记录-
select *from DemoTable;
输出结果
这将产生以下输出-
+-------+ | Value | +-------+ | 20 | | 30 | | 20 | | 40 | | 30 | | 20 | +-------+ 6 rows in set (0.00 sec)
以下是获取值的总出现次数的查询-
select tbl.Value,(SELECT COUNT(*) from DemoTable where Value = tbl.Value) AS Occurrence from DemoTable tbl;
输出结果
这将产生以下输出-
+-------+------------+ | Value | Occurrence | +-------+------------+ | 20 | 3 | | 30 | 2 | | 20 | 3 | | 40 | 1 | | 30 | 2 | | 20 | 3 | +-------+------------+ 6 rows in set (0.00 sec)