IF SQL从MySQL到PostgreSQL的转换

我正在转换PHP脚本,因为数据库已从MysqL切换到Postgresql.

我知道PG没有IF功能,但是有CASE功能.转换此MysqL语句的最佳方法是什么？

  SELECT albums.id, 
         albums.albumname, 
         sum(if(((albums.id=allalbums.albumid) and 
             (allalbums.photoid=$photoid)),1,0)) as inalbum 
    FROM albums, allalbums 
GROUP BY albums.id 
ORDER BY albums.createdate desc

解决方法:

这样的事情应该起作用：

select 
  albums.id, 
  albums.albumname, 
  sum(
   case when ((albums.id=allalbums.albumid) and (allalbums.photoid=$photoid)) then 1
     else 0
   end
  ) as inalbum 
from albums,allalbums 
group by albums.id 
order by albums.createdate desc