Improve CASE statement support.

Try to label CASE columns for a SELECT if not specified with an AS clause.

diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 8dcabc48dbbe927908bae551994dbf8094b1876a..acdf2d7d03dba63af12f3216837a1661f017929a 100644 (file)
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.37 1998/12/04 15:34:30 thomas Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.38 1998/12/13 23:56:43 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -251,8 +251,7 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
                        {
 
                                /*
-                                * look for a column name or a relation name (the default
-                                * behavior)
+                                * look for a column name or a relation name (the default behavior)
                                 */
                                result = transformIdent(pstate, expr, precedence);
                                break;
@@ -358,13 +357,6 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
                                                w->expr = (Node *)a;
                                        }
                                        lfirst(args) = transformExpr(pstate, (Node *) w, precedence);
-
-                                       if (w->result == NULL)
-                                       {
-                                               A_Const *n = makeNode(A_Const);
-                                               n->val.type = T_Null;
-                                               w->result = (Node *)n;
-                                       }
                                }
 
                                if (c->defresult == NULL)
@@ -413,7 +405,7 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
                                        }
                                }
 
-                               /* Convert default clause, if necessary */
+                               /* Convert default result clause, if necessary */
                                if (c->casetype != ptype)
                                {
                                        if (! c->casetype)
@@ -469,8 +461,13 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
                                        elog(ERROR,"WHEN clause must have a boolean result");
 
                                /* result is NULL for NULLIF() construct - thomas 1998-11-11 */
-                               if (w->result != NULL)
-                                       w->result = transformExpr(pstate, (Node *) w->result, precedence);
+                               if (w->result == NULL)
+                               {
+                                       A_Const *n = makeNode(A_Const);
+                                       n->val.type = T_Null;
+                                       w->result = (Node *)n;
+                               }
+                               w->result = transformExpr(pstate, (Node *) w->result, precedence);
                                result = expr;
                                break;
                        }

diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
index e77183387d77a411e380d24105113795ca9cfd2c..35d0db803a2d03e75dded83267449e19e98f2ec1 100644 (file)
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/parser/parse_target.c,v 1.31 1998/12/04 15:34:30 thomas Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/parser/parse_target.c,v 1.32 1998/12/13 23:56:44 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -32,7 +32,7 @@
 
 
 static List *ExpandAllTables(ParseState *pstate);
-static char *FigureColname(Node *expr, Node *resval);
+char *FigureColname(Node *expr, Node *resval);
 
 static Node *SizeTargetExpr(ParseState *pstate,
                           Node *expr,
@@ -867,7 +867,7 @@ ExpandAllTables(ParseState *pstate)
  *       list, we have to guess.
  *
  */
-static char *
+char *
 FigureColname(Node *expr, Node *resval)
 {
        switch (nodeTag(expr))
@@ -881,6 +881,15 @@ FigureColname(Node *expr, Node *resval)
                                        return ((FuncCall *) resval)->funcname;
                        }
                        break;
+               case T_CaseExpr:
+                       {
+                               char *name;
+                               name = FigureColname(((CaseExpr *) expr)->defresult, resval);
+                               if (!strcmp(name, "?column?"))
+                                       name = "case";
+                               return name;
+                       }
+                       break;
                default:
                        break;
        }