Question

我有一张桌子

id    value
1      a
2      a
3      b
4      b
5      b
6      c

我的身份证明是主要的。我总共有2 a，3 b和1 c。所以我想计算每个匹配的主要ID的总重复值

我想要这种格式

id   value_count
1     2
2     2
3     3
4     3
5     3
6     1

Answer 1

尝试此查询：

SELECT a.id, b.valueCnt 
FROM tableA a
INNER JOIN (SELECT a.value, COUNT(a.value) valueCnt
            FROM tableA a GROUP BY a.value) AS B ON a.value = b.value;

检查SQL FIDDLE DEMO

<强>输出

| ID | VALUECNT |
|----|----------|
|  1 |        2 |
|  2 |        2 |
|  3 |        3 |
|  4 |        3 |
|  5 |        3 |
|  6 |        1 |

Answer 2

试试这个

select id, value_count from tablename as a1 
join (select count(*) as value_count, value from tablename group by value) as a2 
on a1.value= a2.value

Answer 3

我建议您使用没有任何连接的子选择：

SELECT  
a.id,(SELECT COUNT(*) FROM tableA WHERE value = a.value) as valueCnt
FROM tableA a

Fiddle Demo

Answer 4

您需要使用子查询。

SELECT table.id , x.value_count
FROM table
INNER JOIN
(SELECT t1.value, count(t1.id) as value_count
FROM table t1
Group by t1.value
) x on x.value = table.value

计算每个唯一ID的值

4 个答案: