如何计算 MySQL 中枢轴 table 上的值？
How to count values on a pivot table in MySQL?
我有两个表 Users 和 Get_cal 如下所示：
用户
id_user(pk)
com
1004
700
1005
700
1006
700
1010
701
1011
701
1012
701
1013
701
1014
800
1015
800
1016
800
1017
800
Get_cal
id_user(fk)
status
1004
ABAN
1004
ABAN
1004
DES
1004
LET
1004
DES
1004
ABAN
1011
LET
1011
LET
1011
ABAN
1015
ABAN
1015
DES
1015
LET
1015
LET
对于 status 列，我有 5 种类型（ABAN、DES、LET、NOANS、OTH）。
我想得到如下结果（按用户状态获取计数）：
id_user
ABAN
DES
LET
NOANS
OTH
1004
3
2
1
0
0
1005
0
0
0
0
0
1006
0
0
0
0
0
1010
0
0
0
0
0
1011
1
0
2
0
0
1012
0
0
0
0
0
1013
0
0
0
0
0
1014
0
0
0
0
0
1015
1
1
2
0
0
1016
0
0
0
0
0
1017
0
0
0
0
0
我不知道如何开始查询，请问有什么建议吗？
您需要在此处进行条件聚合：
SELECT
u.id_user,
COUNT(CASE WHEN c.status = 'ABAN' THEN 1 END) AS ABAN,
COUNT(CASE WHEN c.status = 'DES' THEN 1 END) AS DES,
COUNT(CASE WHEN c.status = 'LET' THEN 1 END) AS LET,
COUNT(CASE WHEN c.status = 'NOANS' THEN 1 END) AS NOANS,
COUNT(CASE WHEN c.status NOT IN ('ABAN', 'DES', 'LET', 'NOAN')
THEN 1 END) AS OTH
FROM Users u
LEFT JOIN Get_cal c
ON c.id_user = u.id_user
GROUP BY
u.id_user
ORDER BY
u.id_user;
如果您的状态在这 5 个案例中始终是静态的。您可以使用 left join 和 group by 以及一些 switch case 条件来解决查询。
SELECT Users.id_user ,
SUM(CASE WHEN Get_cal.status = 'ABAN' THEN 1 ELSE 0 END) AS ABAN ,
SUM(CASE WHEN Get_cal.status = 'DES' THEN 1 ELSE 0 END) AS DES ,
SUM(CASE WHEN Get_cal.status = 'LET' THEN 1 ELSE 0 END) AS LET ,
SUM(CASE WHEN Get_cal.status = 'NOANS' THEN 1 ELSE 0 END) AS NOANS ,
SUM(CASE WHEN Get_cal.status = 'OTH' THEN 1 ELSE 0 END) AS OTH
FROM Users LEFT JOIN Get_cal ON (Users.id_user = Get_cal.id_user) GROUP BY Users.id_user ,Get_cal.id_user
我有两个表 Users 和 Get_cal 如下所示：
用户
| id_user(pk) | com |
|---|---|
| 1004 | 700 |
| 1005 | 700 |
| 1006 | 700 |
| 1010 | 701 |
| 1011 | 701 |
| 1012 | 701 |
| 1013 | 701 |
| 1014 | 800 |
| 1015 | 800 |
| 1016 | 800 |
| 1017 | 800 |
Get_cal
| id_user(fk) | status |
|---|---|
| 1004 | ABAN |
| 1004 | ABAN |
| 1004 | DES |
| 1004 | LET |
| 1004 | DES |
| 1004 | ABAN |
| 1011 | LET |
| 1011 | LET |
| 1011 | ABAN |
| 1015 | ABAN |
| 1015 | DES |
| 1015 | LET |
| 1015 | LET |
对于 status 列，我有 5 种类型（ABAN、DES、LET、NOANS、OTH）。 我想得到如下结果（按用户状态获取计数）：
| id_user | ABAN | DES | LET | NOANS | OTH |
|---|---|---|---|---|---|
| 1004 | 3 | 2 | 1 | 0 | 0 |
| 1005 | 0 | 0 | 0 | 0 | 0 |
| 1006 | 0 | 0 | 0 | 0 | 0 |
| 1010 | 0 | 0 | 0 | 0 | 0 |
| 1011 | 1 | 0 | 2 | 0 | 0 |
| 1012 | 0 | 0 | 0 | 0 | 0 |
| 1013 | 0 | 0 | 0 | 0 | 0 |
| 1014 | 0 | 0 | 0 | 0 | 0 |
| 1015 | 1 | 1 | 2 | 0 | 0 |
| 1016 | 0 | 0 | 0 | 0 | 0 |
| 1017 | 0 | 0 | 0 | 0 | 0 |
我不知道如何开始查询，请问有什么建议吗？
您需要在此处进行条件聚合：
SELECT
u.id_user,
COUNT(CASE WHEN c.status = 'ABAN' THEN 1 END) AS ABAN,
COUNT(CASE WHEN c.status = 'DES' THEN 1 END) AS DES,
COUNT(CASE WHEN c.status = 'LET' THEN 1 END) AS LET,
COUNT(CASE WHEN c.status = 'NOANS' THEN 1 END) AS NOANS,
COUNT(CASE WHEN c.status NOT IN ('ABAN', 'DES', 'LET', 'NOAN')
THEN 1 END) AS OTH
FROM Users u
LEFT JOIN Get_cal c
ON c.id_user = u.id_user
GROUP BY
u.id_user
ORDER BY
u.id_user;
如果您的状态在这 5 个案例中始终是静态的。您可以使用 left join 和 group by 以及一些 switch case 条件来解决查询。
SELECT Users.id_user ,
SUM(CASE WHEN Get_cal.status = 'ABAN' THEN 1 ELSE 0 END) AS ABAN ,
SUM(CASE WHEN Get_cal.status = 'DES' THEN 1 ELSE 0 END) AS DES ,
SUM(CASE WHEN Get_cal.status = 'LET' THEN 1 ELSE 0 END) AS LET ,
SUM(CASE WHEN Get_cal.status = 'NOANS' THEN 1 ELSE 0 END) AS NOANS ,
SUM(CASE WHEN Get_cal.status = 'OTH' THEN 1 ELSE 0 END) AS OTH
FROM Users LEFT JOIN Get_cal ON (Users.id_user = Get_cal.id_user) GROUP BY Users.id_user ,Get_cal.id_user