Index: src/expr.c
==================================================================
--- src/expr.c
+++ src/expr.c
@@ -1579,13 +1579,15 @@
     pTab = p->pSrc->a[0].pTab;
     pExpr = p->pEList->a[0].pExpr;
     iCol = (i16)pExpr->iColumn;
    
     /* Code an OP_VerifyCookie and OP_TableLock for <table>. */
-    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
-    sqlite3CodeVerifySchema(pParse, iDb);
-    sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+    if( pTab->pSchema ){
+      iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      sqlite3CodeVerifySchema(pParse, iDb);
+      sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+    }
 
     /* This function is only called from two places. In both cases the vdbe
     ** has already been allocated. So assume sqlite3GetVdbe() is always
     ** successful here.
     */