Question

im creating a function and i need to choose between two sentences depending on a parameter’s value (PTIPO)

Below is my code

SELECT SUM(
    CASE PTIPO
      WHEN 0 THEN (CASE WHEN (A.NT = 0) THEN A.VALOR ELSE 0 END)
      WHEN 1 THEN (CASE WHEN (A.NT = 1) THEN A.VALOR ELSE 0 END)
      WHEN 2 THEN (CASE WHEN (A.NT = 1) THEN A.VALOR ELSE -A.VALOR END) 
    END)
INTO nresp
FROM mov_caja a
JOIN enc_movp b ON a.docid = b.docid
JOIN c_caja c ON a.cajaid = c.cajaid
WHERE c.cajaid = pcajaid AND( 
    CASE WHEN(PTIPO = 2) --this is what causes the issue.
    THEN
    b.cod_compro = ncompini OR (b.fecha_mov BETWEEN pfecha_ini AND pfecha_fin)
    ELSE
    b.cod_compro != ncompini AND b.fecha_mov BETWEEN pfecha_ini AND pfecha_fin
    END);

The error is “missing keyword”, but i know the problem is the last CASE.
How else could i select between the sentences. Is the case a proper way or should i use another statement ?

Answer 1

A case can return a value, but not an expression. This should do the trick, although I feel it could even be simpler:

SELECT SUM(
    CASE PTIPO
      WHEN 0 THEN (CASE WHEN (A.NT = 0) THEN A.VALOR ELSE 0 END)
      WHEN 1 THEN (CASE WHEN (A.NT = 1) THEN A.VALOR ELSE 0 END)
      WHEN 2 THEN (CASE WHEN (A.NT = 1) THEN A.VALOR ELSE -A.VALOR END) 
    END)
INTO nresp
FROM mov_caja a
JOIN enc_movp b ON a.docid = b.docid
JOIN c_caja c ON a.cajaid = c.cajaid
WHERE 
  c.cajaid = pcajaid AND
  ( 
    (PTIPO = 2 and (b.cod_compro = ncompini OR b.fecha_mov BETWEEN pfecha_ini AND pfecha_fin))
OR
    (PTIPO <> 2 and (b.cod_compro != ncompini AND b.fecha_mov BETWEEN pfecha_ini AND pfecha_fin))
  )