MSSQL ISNULL 을 DB2 에서 사용하는 방법

 

//MSSQL

select ISNULL(max(WR_NO),0) as u_id from vote_Doc

//DB2

EX1)
select CASE WHEN MAX(WR_NO) IS NULL  
            THEN 0                        
            ELSE MAX(WR_NO)  END as u_id
from vote_Doc 

EX2)
select COALESCE(MAX(WR_NO),0)  as u_id
  from vote_Doc


값증가시
만약 MAX(u_id)에 1을 증가하려면

select CASE WHEN MAX(WR_NO) IS NULL  
            THEN 0                        
            ELSE MAX(WR_NO) + 1  END as u_id
from vote_Doc 

== 동일표현식 하나 더

select COALESCE(MAX(WR_NO) + 1,0)  as u_id
  from vote_Doc