From 4d01219849c78749755c6b672f46437ba74e2ebb Mon Sep 17 00:00:00 2001
From: luozenglin <37725793+luozenglin@users.noreply.github.com>
Date: Thu, 30 Dec 2021 10:23:45 +0800
Subject: [PATCH] [fix](lower_case_table_names) Fix the bug of case-sensitive
 aliases in the query when lower_case_table_names=1 is set (#7495)

* [fix](lower_case_table_names) Fix the bug of case-sensitive aliases in the query when lower_case_table_names=1 is set
---
 .../main/java/org/apache/doris/analysis/TableRef.java  |  4 ++++
 .../doris/analysis/TableNameStoredLowercaseTest.java   | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/analysis/TableRef.java b/fe/fe-core/src/main/java/org/apache/doris/analysis/TableRef.java
index de459139c7..30f66a2373 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/analysis/TableRef.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/analysis/TableRef.java
@@ -43,6 +43,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 import java.util.Set;
 
 /**
@@ -148,6 +149,9 @@ public class TableRef implements ParseNode, Writable {
     public TableRef(TableName name, String alias, PartitionNames partitionNames, ArrayList<String> commonHints) {
         this.name = name;
         if (alias != null) {
+            if (Catalog.isStoredTableNamesLowerCase()) {
+                alias = alias.toLowerCase();
+            }
             aliases_ = new String[]{alias};
             hasExplicitAlias_ = true;
         } else {
diff --git a/fe/fe-core/src/test/java/org/apache/doris/analysis/TableNameStoredLowercaseTest.java b/fe/fe-core/src/test/java/org/apache/doris/analysis/TableNameStoredLowercaseTest.java
index 2ad2d08447..0ae7a29c76 100644
--- a/fe/fe-core/src/test/java/org/apache/doris/analysis/TableNameStoredLowercaseTest.java
+++ b/fe/fe-core/src/test/java/org/apache/doris/analysis/TableNameStoredLowercaseTest.java
@@ -98,6 +98,16 @@ public class TableNameStoredLowercaseTest {
         dorisAssert.query(sql2).explainQuery();
     }
 
+    @Test
+    public void testQueryTableAliasCaseInsensitive() throws Exception {
+        String sql1 = "select T1.siteid, t2.k2 from table1 T1 join table2 T2 on t1.siteid = t2.k1" +
+                " where T2.k5 > 1000 order by t1.siteid";
+        dorisAssert.query(sql1).explainQuery();
+
+        String sql2 = "select t.siteid, T.username from (select * from Table1) T";
+        dorisAssert.query(sql2).explainQuery();
+    }
+
     @Test
     public void testCreateSameTableFailed() {
         String TABle2 = "create table db1.TABle2(k1 int, k2 varchar(32), k3 varchar(32)) "