If the alternatives for a CASE construct all have the same typmod,

use that typmod not -1 as the typmod of the CASE result.
Part of response to bug#513.

diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 333333b..339999c 100644 (file)
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.104 2001/10/25 05:49:39 momjian Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.105 2001/11/12 20:05:24 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -806,6 +806,37 @@ exprTypmod(Node *expr)
                case T_RelabelType:
                        return ((RelabelType *) expr)->resulttypmod;
                        break;
+               case T_CaseExpr:
+                       {
+                               /*
+                                * If all the alternatives agree on type/typmod, return
+                                * that typmod, else use -1
+                                */
+                               CaseExpr   *cexpr = (CaseExpr *) expr;
+                               Oid                     casetype = cexpr->casetype;
+                               int32           typmod;
+                               List       *arg;
+
+                               if (!cexpr->defresult)
+                                       return -1;
+                               if (exprType(cexpr->defresult) != casetype)
+                                       return -1;
+                               typmod = exprTypmod(cexpr->defresult);
+                               if (typmod < 0)
+                                       return -1;      /* no point in trying harder */
+                               foreach(arg, cexpr->args)
+                               {
+                                       CaseWhen   *w = (CaseWhen *) lfirst(arg);
+
+                                       Assert(IsA(w, CaseWhen));
+                                       if (exprType(w->result) != casetype)
+                                               return -1;
+                                       if (exprTypmod(w->result) != typmod)
+                                               return -1;
+                               }
+                               return typmod;
+                       }
+                       break;
                default:
                        break;
        }