Index: src/select.c
==================================================================
--- src/select.c
+++ src/select.c
@@ -2367,11 +2367,11 @@
         int iCont, iBreak, iStart;
         assert( p->pEList );
         if( dest.eDest==SRT_Output ){
           Select *pFirst = p;
           while( pFirst->pPrior ) pFirst = pFirst->pPrior;
-          generateColumnNames(pParse, 0, pFirst->pEList);
+          generateColumnNames(pParse, pFirst->pSrc, pFirst->pEList);
         }
         iBreak = sqlite3VdbeMakeLabel(v);
         iCont = sqlite3VdbeMakeLabel(v);
         computeLimitRegisters(pParse, p, iBreak);
         sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak); VdbeCoverage(v);
@@ -2442,11 +2442,11 @@
       */
       assert( p->pEList );
       if( dest.eDest==SRT_Output ){
         Select *pFirst = p;
         while( pFirst->pPrior ) pFirst = pFirst->pPrior;
-        generateColumnNames(pParse, 0, pFirst->pEList);
+        generateColumnNames(pParse, pFirst->pSrc, pFirst->pEList);
       }
       iBreak = sqlite3VdbeMakeLabel(v);
       iCont = sqlite3VdbeMakeLabel(v);
       computeLimitRegisters(pParse, p, iBreak);
       sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak); VdbeCoverage(v);
@@ -3057,11 +3057,11 @@
   /* Set the number of output columns
   */
   if( pDest->eDest==SRT_Output ){
     Select *pFirst = pPrior;
     while( pFirst->pPrior ) pFirst = pFirst->pPrior;
-    generateColumnNames(pParse, 0, pFirst->pEList);
+    generateColumnNames(pParse, pFirst->pSrc, pFirst->pEList);
   }
 
   /* Reassembly the compound query so that it will be freed correctly
   ** by the calling function */
   if( p->pPrior ){

Index: test/capi3c.test
==================================================================
--- test/capi3c.test
+++ test/capi3c.test
@@ -16,10 +16,11 @@
 # $Id: capi3c.test,v 1.23 2009/07/22 07:27:57 danielk1977 Exp $
 #
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
+set testprefix capi3c
 
 # Do not use a codec for tests in this file, as the database file is
 # manipulated directly using tcl scripts (using the [hexio_write] command).
 #
 do_not_use_codec
@@ -1373,6 +1374,28 @@
 } {DATETIME}
 do_test capi3c-24.3 {
   decltype {SELECT (SELECT x FROM (SELECT t5.a AS x)) FROM t5}
 } {INTEGER}
 
+
+# Further tests of sqlite3_column_decltype():
+#
+do_execsql_test 25.0 {
+  CREATE TABLE t11(a VARCHAR(10), b INTEGER);
+  CREATE TABLE t12(a VARCHAR(15), b FLOAT);
+}
+
+foreach {tn sql} {
+  1 "SELECT * FROM t11 UNION ALL SELECT * FROM t12"
+  2 "SELECT * FROM t11 UNION SELECT * FROM t12"
+  3 "SELECT * FROM t11 EXCEPT SELECT * FROM t12"
+  4 "SELECT * FROM t11 INTERSECT SELECT * FROM t12"
+
+  5 "SELECT * FROM t11 UNION ALL SELECT * FROM t12 ORDER BY 1"
+  6 "SELECT * FROM t11 UNION SELECT * FROM t12 ORDER BY 1"
+  7 "SELECT * FROM t11 EXCEPT SELECT * FROM t12 ORDER BY 1"
+  8 "SELECT * FROM t11 INTERSECT SELECT * FROM t12 ORDER BY 1"
+} {
+  do_test 25.$tn { decltype $sql } {VARCHAR(10) INTEGER}
+}
+
 finish_test