diff --git a/contrib/tablefunc/tablefunc.c b/contrib/tablefunc/tablefunc.c
index 3388fab..878255e 100644
--- a/contrib/tablefunc/tablefunc.c
+++ b/contrib/tablefunc/tablefunc.c
@@ -1317,12 +1317,12 @@ build_tuplestore_recursively(char *key_fld,
 		StringInfoData chk_current_key;
 
 		/* First time through, do a little more setup */
-		if (level == 0)
+		if (level == 1)
 		{
 			/*
 			 * Check that return tupdesc is compatible with the one we got
-			 * from the query, but only at level 0 -- no need to check more
-			 * than once
+			 * from the query, but only at the first level -- no need to check
+			 * more than once
 			 */
 
 			if (!compatConnectbyTupleDescs(tupdesc, spi_tupdesc))