Mysql左联接不能按预期工作

Question

I am attempting a simple left join that is giving me problems. I need all the customers listed (table a) regardless of whether or not they have an invoice (table b) between a certain date range. Both of my attempts have yielded the only customer that has an invoice for that period:

select b.clientname,a.* from invdata a
   left join clidata b on a.clidataid=b.recordid
      where b.recstatus=1 and b.isactive=1
      and a.reccreate between '2015-04-01 00:00:00' and '2015-04-30 23:59:59';

OR

select a.clientname,b.* from clidata a
   left join invdata b on a.recordid=b.clidataid
      where a.recstatus=1 and a.isactive=1
      and b.reccreate between '2015-04-01 00:00:00' and '2015-04-30 23:59:59';

Little help, please. Thanks!!

Answer 1

Left join with where condition is inner join and will filter the data as per the where condition, you may need to move the where condition into joining condition

  select b.clientname,a.* from invdata a
  left join clidata b on a.clidataid=b.recordid
  and b.recstatus=1 and b.isactive=1
  and a.reccreate between '2015-04-01 00:00:00' and '2015-04-30 23:59:59';