From 26a4e5c8627cce89659fd15aa8fc8078eb30a8a1 Mon Sep 17 00:00:00 2001
From: Huqing Yan <yanhuqing666@gmail.com>
Date: Tue, 14 Dec 2021 13:41:32 +0800
Subject: [PATCH] inner-1519 (#3000)

* inner-1519

* subquery contains only one table
---
 .../dble/plan/optimizer/JoinChooser.java      | 29 ++++++++++++++-----
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/src/main/java/com/actiontech/dble/plan/optimizer/JoinChooser.java b/src/main/java/com/actiontech/dble/plan/optimizer/JoinChooser.java
index 21dbbec6e..7382b5f0f 100644
--- a/src/main/java/com/actiontech/dble/plan/optimizer/JoinChooser.java
+++ b/src/main/java/com/actiontech/dble/plan/optimizer/JoinChooser.java
@@ -665,19 +665,34 @@ public class JoinChooser {
     }
 
 
-    private ERTable getERKey(PlanNode tn, Item c) {
-        if (!(c instanceof ItemField))
-            return null;
-        if (tn.type() != PlanNode.PlanNodeType.TABLE && !PlanUtil.isERNode(tn)) {
-            return null;
+    private boolean onlyContainsOneTable(PlanNode queryNode) {
+        PlanNode child = queryNode.getChildren().get(0);
+        if (child.type() == PlanNode.PlanNodeType.TABLE) {
+            return true;
+        } else if (child.type() == PlanNode.PlanNodeType.QUERY) {
+            return onlyContainsOneTable(child);
+        } else {
+            return false;
+        }
+    }
+
+    private ERTable getERKey(PlanNode tn, Item column) {
+        if (!(column instanceof ItemField))
+            return null;
+        Pair<TableNode, ItemField> pair = null;
+        if (tn.type() == PlanNode.PlanNodeType.QUERY && onlyContainsOneTable(tn)) {
+            pair = PlanUtil.findColumnInTableLeaf((ItemField) column, tn);
+        } else if (tn.type() != PlanNode.PlanNodeType.TABLE && !PlanUtil.isERNode(tn)) {
+            return null;
+        } else {
+            pair = PlanUtil.findColumnInTableLeaf((ItemField) column, tn);
         }
-        Pair<TableNode, ItemField> pair = PlanUtil.findColumnInTableLeaf((ItemField) c, tn);
         if (pair == null)
             return null;
         TableNode tableNode = pair.getKey();
         ItemField col = pair.getValue();
         ERTable erTable = new ERTable(tableNode.getSchema(), tableNode.getPureName(), col.getItemName());
-        if (tn.type() == PlanNode.PlanNodeType.TABLE) {
+        if (tn.type() == PlanNode.PlanNodeType.TABLE || tn.type() == PlanNode.PlanNodeType.QUERY) {
             return erTable;
         } else {
             List<ERTable> erList = ((JoinNode) tn).getERkeys();