Question

我想创建一个依赖于其他两个表的SELECT查询

表1： tbcategories

id      name   
--      ----
1       category1
2       category2
3       category3

表2： tbgroups

id      category    name   
--      --------    ----
1       1           group1
2       1           group2
3       2           group3

表3： tbchilds

id      group       name   
--      -----       ----
1       group1      child1
2       group1      child2
3       group2      child3
4       group2      child4
5       group3      child5

我需要什么 - 查询语法给了我所有的孩子（tbchilds）他们的＆＃34;组＆＃34;是特定类别。例如：给我所有的孩子＆＃34;＆＃34;＆＃34; category1 =输出将是：

child1
child2
child3
child4

10X

Answer 1

SELECT *
FROM tbcategories a
INNER JOIN 
        tbgroups b
    ON
        a.id = b.category
JOIN
        tbchilds t3
    ON
        t2.name = t3.group
WHERE
    t1.name ='category1'

Answer 2

这个未经测试的查询应该能得到预期的结果：

select t3.name from tbcategories t1 join tbgroups t2 on t1.id = t2.category   join tbchilds t3 on t2.name=t3.`group` where t1.name ='category1'

Answer 3

Best example for PHP MySQL joins

<强>尝试

SELECT ch.name FROM tbchilds ch 
  JOIN tbgroups gr ON ch.group=gr.name 
  JOIN tbcategories cat ON cat.id=gr.category 
WHERE cat.name='category1';

Answer 4

您可以尝试这样的事情：

SELECT C.name
FROM tbcategories A 
INNER JOIN tbgroups B
ON A.id = B.category
INNER JOIN tbchilds C
ON B.name = C.group
WHERE A.name = 'CATEGORY1';

希望这对你有所帮助。

Answer 5

使用以下查询 -

SELECT CH.name FROM tbgroups AS G

INNER JOIN tbchilds AS CH ON CH.group = G.id

INNER JOIN tbcategories AS C ON C.id = G.category

WHERE C.id = <CategoryID>;

SELECT查询依赖于其他两个表

5 个答案: