mysql - 选择查询两位数据

Question

表(userData)如下所示:

userId    property    value
1         AGE         28
1         GENDER      M
2         AGE         28
2         GENDER      F
3         AGE         29
3         GENDER      F
4         AGE         29
4         GENDER      F

所以我想要得到类似的东西:

Gender    Age    Count
M         28     1
F         28     1
F         29     2

Answer 1

类似这样的吗？

SELECT
    ud1.value AS gender,
    ud2.value AS age,
    COUNT(*) AS c
FROM userData ud1
JOIN userData ud2 ON
    ud1.userId = ud2.userId AND
    ud2.property = 'AGE'
WHERE ud1.property = 'GENDER'
GROUP BY gender, age