Index: src/select.c
==================================================================
--- src/select.c
+++ src/select.c
@@ -1698,10 +1698,12 @@
   memset(&sNC, 0, sizeof(sNC));
   sNC.pSrcList = pSelect->pSrc;
   a = pSelect->pEList->a;
   for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
     p = a[i].pExpr;
+    if( pCol->zType ) break;
+    if( pCol->zColl ) break;
     pCol->zType = sqlite3DbStrDup(db, columnType(&sNC, p,0,0,0, &pCol->szEst));
     szAll += pCol->szEst;
     pCol->affinity = sqlite3ExprAffinity(p);
     if( pCol->affinity==0 ) pCol->affinity = SQLITE_AFF_NONE;
     pColl = sqlite3ExprCollSeq(pParse, p);

Index: test/subquery.test
==================================================================
--- test/subquery.test
+++ test/subquery.test
@@ -581,7 +581,17 @@
   execsql {
     SELECT (SELECT (SELECT max(c7)+max(c8)+max(c9) FROM t9) FROM t8) FROM t7
   }
 } {30303}
 }  ;############# Disabled
+
+# 2015-04-21.
+# Verify that a memory leak in the table column type and collation analysis
+# is plugged.
+#
+do_execsql_test subquery-8.1 {
+  CREATE TABLE t8(a TEXT, b INT);
+  SELECT (SELECT 0 FROM (SELECT * FROM t1)) AS x WHERE x;
+  SELECT (SELECT 0 FROM (SELECT * FROM (SELECT 0))) AS x WHERE x;
+} {}
 
 finish_test