需要一个sql查询来查找连接两个表但比较第二个表中的多行的结果

Question

Below given are two sample tables

Table: post

id  title       desc             status
1   test        testdesc         active
2   test1       testdesc2        active

Table: post_meta

 id     post_id         meta_key          meta_value
 1        1             _customer_user    342
 2        1             date_registered   2019-03-21
 3        2             _customer_user    342
 4        2             date_registered   2019-03-22

I want an sql query to find those who registered on 2019-03-21 and are active. Want result like below.

id  cusomerid   registered_date   
1    342         2019-03-21

Answer 1

You can try below -

DEMO

select a.id, b.meta_Value as customerid, b1.meta_value as registrationdate
from post a left join post_meta b 
on a.id=b.post_id and b.meta_key='_customer_user'
left join post_meta b1 
on a.id=b1.post_id and b1.meta_key='date_registered'
where status='active' and b1.meta_value='2019-03-21'

OUTPUT:

id  customerid  registrationdate
1   342         2019-03-21