选择和内部联接中的DB2 SQL If语句

Question

I have a simple query. I am doing a simple select (see below). It works now I want to do an inner join to another table and also do an if statement inside. I have been searching the web and cannot find what I am looking for.

I basically want to join into the item master table and if it is type 'E' do something else do something.

Can someone point me in the right direction?

EXEC SQL Declare RSCURSOR cursor for
    SELECT A.*, B.*
FROM HPO A
INNER JOIN IIML01 B on A.PPROD = B.IPROD
IF B.IITYP <> 'E';
PCMT = B.IDESC;
ELSE;
PCMT = A.PCMT ;
WHERE PORD = :PON AND PLINE = :LIN;

EXEC SQL  Open RSCURSOR;

EXEC SQL SET RESULT SETS Cursor RSCURSOR;

IF SQLSTATE = '00000';
  RSL = '00';
ELSEIF SQLSTATE = '02000';
  RSL = '10';
ELSE;
  RSL = '20';
ENDIF;    

This is what I have in RPG fixed:

     C     PPROD         CHAIN     IPI100IM                           99
     C     *IN99         IFEQ      '0'
     C
     C     IITYP         IFNE      'E'
     C                   EVAL      RS(CNT).PCMT = IDESC                         
     C                   ELSE
     C                   EVAL      RS(CNT).PCMT = PCMT                          
     C                   ENDIF              

Answer 1

Not totally clear, but I think you want this:

SELECT A.*, B.*
FROM HPO A
INNER JOIN IIML01 B on A.PPROD = B.IPROD 
  AND CASE WHEN B.IITYP <> 'E' THEN B.IDESC ELSE A.PCMT END = PCMT
WHERE PORD = :PON AND PLINE = :LIN;

---

Based on the comment you want something like this:

SELECT CASE WHEN B.IITYP <> 'E' THEN B.IDESC ELSE A.PCMT END AS PCMT, A.*, B.*
FROM HPO A
INNER JOIN IIML01 B on A.PPROD = B.IPROD 
WHERE PORD = :PON AND PLINE = :LIN;