Mysql 与count左连接

对不起，所有

我是个新手，在左键和count连接时有问题

结构表A：

结构表B:

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

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

结构表C:

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

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

我希望从这样的结果中得到示例：

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

注意：尽管行为null/zero，但从字段“count”中仍然显示零

谢谢师父

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

---

因为您没有发布查询，所以看不出您做错了什么，但这应该可以满足您的需要：

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

---

a桌去哪了？谢谢师父。。。这个查询太棒了！！这是工作