mysql - 左加入计数

Question

对不起大家...

我是新手，左加入计数有问题

结构表A：

结构表 B：

----------------------
|Branch_code   | NIK
----------------------
'IDJB001BEC', '1300001'
'IDJB001BEC', '1300002'
'IDPA001PPA', '1300003'
'IDJK001MAG', '1300004'
'IDJB001BEC', '1300005'
'IDJB001BEC', ''
'IDBTNCTR', ''

结构表 C：

|branch_code|
'IDBE001BGK'
'IDBE002BGK'
'IDBTNCTR'
'IDJB001BEC'
'IDJK001HO'
'IDJK001MAG'
'IDJK001MPI'
'IDJK002MCL'
'IDJK002MPB'
'IDJK003KDY'

我希望从这样的结果中获得样本：

|Branch_code|count|
'IDJK001MAG'  0
'IDJK001MPI'  0
'IDJK002MCL'  3
'IDJK002MPB'  5
'IDJK003KDY'  4

注意：尽管该行为空/零，但“计数”字段仍显示零。

感谢师父

Answer 1

试试这个：

SELECT c.branch_code, COUNT(b.nik) 
FROM tablec c 
LEFT JOIN tableb b ON c.branch_code, b.branch_code 
GROUP BY c.branch_code

Answer 2

select a.branch_code,count(a.nik) as nik_count from table a left join table b
on a.branch_code=b.branch_code

group by a.branch_code

Answer 3

由于您没有发布查询，因此看不到您做错了什么，但这应该可以满足您的需求：

SELECT 
c.branch_code, 
COUNT(b.nik) 
FROM tablec c 
LEFT JOIN tableb b ON c.branch_code = b.branch_code 
GROUP BY c.branch_code

SQL小提琴