mysql - 如何从两个不同的表中获取两个不同的列值 invert 一个值表依赖于另一个表值

Question

下面的查询是我之前使用的...但是我想结合这两个查询以提高性能

select a, b, c
  from table1
 where d LIKE 'xxx'
   and f like 'yyyy'
 order by b desc;

我正在执行上述查询并读取值。

对于来自上述查询的每个 b 值，再次在循环中执行以下查询。

select count(*) 
  from table2 where b=? AND js_email_id IN 
(
  select js_email_id 
    from js_initialsignup 
   where UCase(jsaccountstatus) LIKE UCase('live') 
     AND UCase(js_status) LIKEUCase('accepted')
)

如何合并两个查询并一次获取计数和值？

Answer 1

select a,b,c,
       (select count(*) 
from table2 where b=a.b AND js_email_id IN 
(
  select js_email_id 
  from js_initialsignup 
  where UCase(jsaccountstatus) LIKE UCase('live') 
    AND UCase(js_status) LIKEUCase('accepted')
)) as cnt

from table1 a