From 876a93b17f0d55e8e778e596d970395c68198681 Mon Sep 17 00:00:00 2001
From: Cheng Wang <cheng.wang@kyligence.io>
Date: Tue, 5 Jul 2016 10:16:20 +0800
Subject: [PATCH] KYLIN 1792 it fixed when join contains subquery, kylin will
 return no results.

---
 .../java/org/apache/kylin/query/relnode/OLAPJoinRel.java  | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/query/src/main/java/org/apache/kylin/query/relnode/OLAPJoinRel.java b/query/src/main/java/org/apache/kylin/query/relnode/OLAPJoinRel.java
index dc16dad..f66351b 100644
--- a/query/src/main/java/org/apache/kylin/query/relnode/OLAPJoinRel.java
+++ b/query/src/main/java/org/apache/kylin/query/relnode/OLAPJoinRel.java
@@ -117,11 +117,14 @@ public class OLAPJoinRel extends EnumerableJoin implements OLAPRel {
         this.isTopJoin = !this.context.hasJoin;
         this.context.hasJoin = true;
 
+        int nJoinPossibility = 0;
+
         // as we keep the first table as fact table, we need to visit from left to right
         implementor.visitChild(this.left, this);
         if (this.context != implementor.getContext() || ((OLAPRel) this.left).hasSubQuery()) {
             this.hasSubQuery = true;
             // if child is also an OLAPJoin, then the context has already been popped
+            nJoinPossibility--;
             if (this.context != implementor.getContext()) {
                 implementor.freeContext();
             }
@@ -129,6 +132,7 @@ public class OLAPJoinRel extends EnumerableJoin implements OLAPRel {
         implementor.visitChild(this.right, this);
         if (this.context != implementor.getContext() || ((OLAPRel) this.right).hasSubQuery()) {
             this.hasSubQuery = true;
+            nJoinPossibility++;
             // if child is also an OLAPJoin, then the context has already been popped
             if (this.context != implementor.getContext()) {
                 implementor.freeContext();
@@ -136,6 +140,7 @@ public class OLAPJoinRel extends EnumerableJoin implements OLAPRel {
         }
 
         this.columnRowType = buildColumnRowType();
+
         if (isTopJoin) {
             this.context.afterJoin = true;
         }
@@ -152,6 +157,16 @@ public class OLAPJoinRel extends EnumerableJoin implements OLAPRel {
             join.setType(joinType);
 
             this.context.joins.add(join);
+        } else if (0 != nJoinPossibility) {
+            //When join contains subquery, the join-condition fields of fact_table will add into context.
+            Map<TblColRef, TblColRef> joinCol = new HashMap<TblColRef, TblColRef>();
+            translateJoinColumn((RexCall) this.getCondition(), joinCol);
+
+            for (Map.Entry<TblColRef, TblColRef> columnPair : joinCol.entrySet()) {
+                TblColRef fromCol = (-1 == nJoinPossibility ? columnPair.getValue() : columnPair.getKey());
+                this.context.groupByColumns.add(fromCol);
+            }
+            joinCol.clear();
         }
     }
 
-- 
2.7.4 (Apple Git-66)