如何使用mysql连接查询在一列中的两个位置？

Question

im using mysql for database project , i have one mysql table taxonomy .

i needed post_id with condition tax_id = 1 and tax_id = 2 in mysql , also if i want usable for join sql .

example :

post_id | tax_id
------- | ------
  1     |   1
  1     |   2
  2     |   1
  2     |   3 

i want postid equal with condation taxid equal 1 and 2

for example my using this sql but not working :

SELECT * FROM `term_relationships` WHERE tax_id = 9 AND tax_id = 1120 ;

Answer 1

Here's one option using conditional aggregation :

select post_id
from term_relationships
group by post_id
having count(case when term_taxonomy_id in (9, 1120) then 1 end) = 2

• SQL Fiddle Demo

Answer 2

Try this...

You can use IN clause.

SELECT * FROM `term_relationships` WHERE term_taxonomy_id in (9,1120);