1 files changed, 16 insertions, 0 deletions
diff --git a/src/expr.c b/src/expr.c
index 3141cd9db..aa9cc7b52 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1415,6 +1415,22 @@ int sqlite3ExprIsConstantOrFunction(Expr *p, u8 isInit){
   return exprIsConst(p, 4+isInit, 0);
 }
 
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/*
+** Walk an expression tree.  Return 1 if the expression contains a
+** subquery of some kind.  Return 0 if there are no subqueries.
+*/
+int sqlite3ExprContainsSubquery(Expr *p){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.eCode = 1;
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.xSelectCallback = selectNodeIsConstant;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode==0;
+}
+#endif
+
 /*
 ** If the expression p codes a constant integer that is small enough
 ** to fit in a 32-bit integer, return 1 and put the value of the integer