[tarantool-patches] [PATCH] sql: assertion fail on nested select

[N.Tatunov]

To optimize the select-subquery tarantool uses
subquery flattening function which is only used
with respect to some restrictions. One of them
was implemented improperly.

Closes: #3353
---

Issue: https://github.com/tarantool/tarantool/issues/3353
Branch: https://github.com/tarantool/tarantool/tree/N_Tatunov/gh-3353-assertion-on-nested-select

 src/box/sql/select.c           |  6 +++---
 test/sql-tap/subquery.test.lua | 48 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/src/box/sql/select.c b/src/box/sql/select.c
index 54f78a9..c035691 100644
--- a/src/box/sql/select.c
+++ b/src/box/sql/select.c
@@ -3893,14 +3893,14 @@ flattenSubquery(Parse * pParse,		/* Parsing context */
 	 * queries.
 	 */
 	if (pSub->pPrior) {
-		if (pSub->pOrderBy) {
-			return 0;	/* Restriction 20 */
-		}
 		if (isAgg || (p->selFlags & SF_Distinct) != 0
 		    || pSrc->nSrc != 1) {
 			return 0;
 		}
 		for (pSub1 = pSub; pSub1; pSub1 = pSub1->pPrior) {
+			if (pSub1->pOrderBy) {
+				return 0;	/* Restriction 20 */
+			}
 			testcase((pSub1->
 				  selFlags & (SF_Distinct | SF_Aggregate)) ==
 				 SF_Distinct);
diff --git a/test/sql-tap/subquery.test.lua b/test/sql-tap/subquery.test.lua
index 06631c1..d1e17b3 100755
--- a/test/sql-tap/subquery.test.lua
+++ b/test/sql-tap/subquery.test.lua
@@ -1,6 +1,6 @@
 #!/usr/bin/env tarantool
 test = require("sqltester")
-test:plan(69)
+test:plan(73)
 
 --!./tcltestrunner.lua
 -- 2005 January 19
@@ -926,6 +926,52 @@ test:do_execsql_test(
         -- </subquery-8.1>
     })
 
+test:do_catchsql_test(
+	"subquery-9.0",
+	[[
+		DROP TABLE IF EXISTS table1;
+		CREATE TABLE table1 (id VARCHAR(100) PRIMARY KEY);
+		INSERT INTO table1 VALUES ('abc'), ('abd');
+	]], {
+		-- <subquery-9.0>
+		0
+		-- <subquery-9.0>
+	})
+
+test:do_catchsql_test(
+	"subquery-9.1",
+	[[
+		SELECT * FROM (SELECT * FROM table1 UNION ALL
+                               SELECT * FROM table1 ORDER BY 1 UNION ALL
+			       SELECT * FROM table1);
+	]], {
+		-- <subquery-9.1>
+		1, 'ORDER BY clause should come after UNION ALL not before'
+		-- <subquery-9.1>
+	})
+
+test:do_execsql_test(
+	"subquery-9.2",
+	[[
+		SELECT 'abc' FROM (SELECT * FROM table1 UNION ALL
+                                   SELECT * FROM table1 UNION ALL
+				   SELECT * FROM table1 ORDER BY 1);
+	]], {
+		-- <subquery-9.2>
+		'abc','abc','abc','abc','abc','abc'
+		-- <subquery-9.2>
+	})
 
+test:do_catchsql_test(
+	"subquery-9.3",
+	[[
+		SELECT * FROM (SELECT * FROM table1 ORDER BY 1 UNION All
+                               SELECT * FROM table1 UNION All
+			       SELECT * FROM table1);
+	]], {
+             -- <subquery-9.3>
+             1, 'ORDER BY clause should come after UNION ALL not before'
+             -- <subquery-9.3>
+	})
 
 test:finish_test()
-- 
2.7.4