Index: src/select.c
==================================================================
--- src/select.c
+++ src/select.c
@@ -882,11 +882,11 @@
       Table *pTab = 0;            /* Table structure column is extracted from */
       Select *pS = 0;             /* Select the column is extracted from */
       int iCol = pExpr->iColumn;  /* Index of column in pTab */
       testcase( pExpr->op==TK_AGG_COLUMN );
       testcase( pExpr->op==TK_COLUMN );
-      while( ALWAYS(pNC) && !pTab ){
+      while( pNC && !pTab ){
         SrcList *pTabList = pNC->pSrcList;
         for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
         if( j<pTabList->nSrc ){
           pTab = pTabList->a[j].pTab;
           pS = pTabList->a[j].pSelect;
@@ -893,22 +893,32 @@
         }else{
           pNC = pNC->pNext;
         }
       }
 
-      if( NEVER(pTab==0) ){
+      if( pTab==0 ){
         /* At one time, code such as "SELECT new.x" within a trigger would
         ** cause this condition to run.  Since then, we have restructured how
         ** trigger code is generated and so this condition is no longer 
-        ** possible.  But it seems prudent to keep the test in place in
-        ** case something else changes.
-        */
-        zType = "TEXT";
+        ** possible. However, it can still be true for statements like
+        ** the following:
+        **
+        **   CREATE TABLE t1(col INTEGER);
+        **   SELECT (SELECT t1.col) FROM FROM t1;
+        **
+        ** when columnType() is called on the expression "t1.col" in the 
+        ** sub-select. In this case, set the column type to NULL, even
+        ** though it should really be "INTEGER".
+        **
+        ** This is not a problem, as the column type of "t1.col" is never
+        ** used. When columnType() is called on the expression 
+        ** "(SELECT t1.col)", the correct type is returned (see the TK_SELECT
+        ** branch below.  */
         break;
       }
 
-      assert( pTab );
+      assert( pTab && pExpr->pTab==pTab );
       if( pS ){
         /* The "table" is actually a sub-select or a view in the FROM clause
         ** of the SELECT statement. Return the declaration type and origin
         ** data for the result-set column of the sub-select.
         */
@@ -918,11 +928,11 @@
           ** test case misc2.2.2) - it always evaluates to NULL.
           */
           NameContext sNC;
           Expr *p = pS->pEList->a[iCol].pExpr;
           sNC.pSrcList = pS->pSrc;
-          sNC.pNext = 0;
+          sNC.pNext = pNC;
           sNC.pParse = pNC->pParse;
           zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol); 
         }
       }else if( ALWAYS(pTab->pSchema) ){
         /* A real table */

Index: test/capi3c.test
==================================================================
--- test/capi3c.test
+++ test/capi3c.test
@@ -1318,7 +1318,41 @@
     sqlite3_column_text16 $STMT 2
     sqlite3_column_text $STMT 3
   } {one}
   sqlite3_finalize $STMT
 }
+
+# Test decltype on some SELECT statements that contain sub-selects.
+#
+proc decltype {zSql} {
+  set ret [list]
+  set STMT [sqlite3_prepare_v2 db $zSql -1 TAIL]
+  for {set i 0} {$i < [sqlite3_column_count $STMT]} {incr i} {
+    lappend ret [sqlite3_column_decltype $STMT $i]
+  }
+  sqlite3_finalize $STMT
+  return $ret
+}
+do_test capi3c-24.1 {
+  execsql { CREATE TABLE t5(a INTEGER, b STRING, c DATETIME) }
+  decltype {SELECT * FROM t5}
+} {INTEGER STRING DATETIME}
+do_test capi3c-24.2 {
+  decltype {SELECT (SELECT c) FROM t5}
+} {DATETIME}
+do_test capi3c-24.3 {
+  decltype {SELECT (SELECT * FROM (SELECT c)) FROM t5}
+} {DATETIME}
+do_test capi3c-24.4 {
+  decltype {SELECT * FROM (SELECT * FROM t5 ORDER BY c LIMIT 1) ORDER BY b}
+} {INTEGER STRING DATETIME}
+do_test capi3c-24.5 {
+  decltype {
+    SELECT (SELECT x FROM (SELECT c AS x)) 
+    FROM (SELECT * FROM t5 ORDER BY c LIMIT 1) ORDER BY b
+  }
+} {DATETIME}
+do_test capi3c-24.3 {
+  decltype {SELECT (SELECT x FROM (SELECT t5.a AS x)) FROM t5}
+} {INTEGER}
 
 finish_test