Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/3033#discussion_r96420110
--- Diff:
flink-libraries/flink-table/src/test/scala/org/apache/flink/table/api/scala/batch/sql/DataSetSingleRowJoinTest.scala
---
@@ -192,4 +192,145 @@ class SingleRowJoinTest extends TableTestBase {
util.verifySql(query, expected)
}
+
+ @Test
+ def testSingleRowJoinLeftOuterJoin(): Unit = {
+ val util = batchTestUtil()
+ util.addTable[(Int, Int)]("A", 'a1, 'a2)
+ util.addTable[(Int, Int)]("B", 'b1, 'b2)
+
+ val queryLeftJoin =
+ "SELECT a2 FROM A " +
+ "LEFT JOIN " +
+ "(SELECT COUNT(*) AS cnt FROM B) " +
+ "AS x " +
+ "ON a1 < cnt"
+
+ val expected =
+ unaryNode(
+ "DataSetCalc",
+ unaryNode(
+ "DataSetSingleRowJoin",
+ batchTableNode(0),
+ term("where", "<(a1, cnt)"),
+ term("join", "a1", "a2", "cnt"),
+ term("joinType", "NestedLoopJoin")
+ ),
+ term("select", "a2")
+ ) + "\n" +
+ unaryNode(
+ "DataSetAggregate",
+ unaryNode(
+ "DataSetUnion",
+ unaryNode(
+ "DataSetValues",
+ unaryNode(
+ "DataSetCalc",
+ batchTableNode(1),
+ term("select", "0 AS $f0")),
+ tuples(List(null)), term("values", "$f0")
+ ),
+ term("union", "$f0")
+ ),
+ term("select", "COUNT(*) AS cnt")
+ )
+
+ util.verifySql(queryLeftJoin, expected)
+ }
+
+ @Test
+ def testSingleRowJoinRightOuterJoin(): Unit = {
+ val util = batchTestUtil()
+ util.addTable[(Int, Int)]("A", 'a1, 'a2)
+ util.addTable[(Int, Int)]("B", 'b1, 'b2)
+
+ val queryRightJoin =
+ "SELECT a2 FROM A " +
+ "RIGHT JOIN " +
+ "(SELECT COUNT(*) AS cnt FROM B) " +
--- End diff --
This should not be allowed. It should rather be
```
SELECT a2
FROM
(SELECT COUNT(*) AS cnt FROM B)
RIGHT JOIN
A
```
The single input must always be on the inner side and the multi input on
the outer side.
We should add test cases for left and right outer join to check that this
condition is not violated.
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