SELECT查询依赖于其他两个表

I would like to make a SELECT query that depends on two other tables

我想做一个依赖于其他两个表的SELECT查询

table 1: tbcategories

表1:tbcategories

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

table 2: tbgroups

表2:tbgroups

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

table 3: tbchilds

表3:tbchilds

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

What I need - The query syntax which gives me all the childs (tbchilds) that their "group" is on specific category. For example: give me all the childs that "under" category1 = the output will be:

我需要的 - 查询语法,它给了我所有的孩子(tbchilds)他们的“组”在特定类别。例如:给我所有的孩子“在”category1 =输出将是:

child1
child2
child3
child4

10X

5 个解决方案

#1

Best example for PHP MySQL joins

PHP MySQL连接的最佳示例

Try

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';

#2

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'

#3

this untested query should get you the expected result:

这个未经测试的查询应该会得到预期的结果:

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'

#4

Use Following Query -

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>;

#5

You can try somthing like this:

你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';

Hope this is helpful to you.

希望这对你有所帮助。

#1