Question

我在以下结构中有两个表

table_1

uid | name | age
1   | John | 24
2   | Adam | 35
3   | Sara | 26

TABLE_2

id | uid | meta_key | meta_value
1  | 2   | location | NY
2  | 2   | school   | NYU
3  | 3   | Location | NY
4  | 3   | school   | XYZ
6  | 1   | location | NY
6  | 1   | school   | NYU

我要做的是从table_1中选择位置为纽约且学校为纽约大学的用户

这是我尝试使用但没有运气的查询

SELECT
  tabl_1.uid
FROM `tabl_1`, `tabl_2`
WHERE
  tabl_1.uid = tabl_2.uid
  AND table_2.meta_key IN ('location', 'school')
  AND table_2.meta_value IN ('NY', 'NYU')
ORDER BY tabl_1.uid ASC

如果你有一个有效的查询或一个非常感谢的解决方案的链接，我已经无处运气了，我感谢你。

Answer 1

你应该试试

SELECT t1.uid
FROM tabl_1 t1 INNER JOIN tabl_2 t2
ON t1.uid = t2.uid AND t2.meta_key = 'location' AND t2.meta_value = 'NY'
INNER JOIN tabl_2 t3
ON t1.uid = t3.uid AND t3.meta_key = 'school' AND t3.meta_value = 'NYU'

检查http://sqlfiddle.com/#!2/f35ef/1/0

上的结果

Answer 2

尝试： http://sqlfiddle.com/#!2/cc913c/27

SELECT t.* FROM 
(
  SELECT a.uid, a.name, GROUP_CONCAT(b.meta_key, b.meta_value) AS mkv 
  FROM table_1 a
  LEFT JOIN table_2 b ON b.uid = a.uid 
  GROUP BY a.uid, a.name
) AS t
WHERE 
  t.mkv IN ("schoolNYU,locationNY");

Answer 3

尝试

SELECT table_1.Uid
FROM table_1
INNER JOIN table_2 ON table_1.Uid = table_2.Uid
WHERE (table_2.meta_key = 'location' AND table_2.meta_value = 'NY')
AND (table_2.meta_key = 'school' AND table_2.meta_valaye = 'NYU')

将多个值选择为多个表中的同一个键

3 个答案: