From afcd6f9f093677ae2f73294885862877e5de2e49 Mon Sep 17 00:00:00 2001
From: Ivan Blinkov <github@blinkov.ru>
Date: Thu, 6 Dec 2018 17:30:10 +0300
Subject: [PATCH] Make substring function name case-insensitive + add two
 aliases #3704

---
 dbms/src/Functions/substring.cpp                              | 4 +++-
 .../0_stateless/00765_sql_compatibility_aliases.reference     | 3 +++
 .../queries/0_stateless/00765_sql_compatibility_aliases.sql   | 3 +++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/dbms/src/Functions/substring.cpp b/dbms/src/Functions/substring.cpp
index e0a6d707243..7263f3ec595 100644
--- a/dbms/src/Functions/substring.cpp
+++ b/dbms/src/Functions/substring.cpp
@@ -166,7 +166,9 @@ public:
 
 void registerFunctionSubstring(FunctionFactory & factory)
 {
-    factory.registerFunction<FunctionSubstring>();
+    factory.registerFunction<FunctionSubstring>(FunctionFactory::CaseInsensitive);
+    factory.registerAlias("substr", FunctionSubstring::name, FunctionFactory::CaseInsensitive);
+    factory.registerAlias("mid", FunctionSubstring::name, FunctionFactory::CaseInsensitive); /// from MySQL dialect
 }
 
 }
diff --git a/dbms/tests/queries/0_stateless/00765_sql_compatibility_aliases.reference b/dbms/tests/queries/0_stateless/00765_sql_compatibility_aliases.reference
index 439957db622..152c2182d69 100644
--- a/dbms/tests/queries/0_stateless/00765_sql_compatibility_aliases.reference
+++ b/dbms/tests/queries/0_stateless/00765_sql_compatibility_aliases.reference
@@ -4,3 +4,6 @@ foo
 FOO
 baz
 2
+fo
+oo
+o
diff --git a/dbms/tests/queries/0_stateless/00765_sql_compatibility_aliases.sql b/dbms/tests/queries/0_stateless/00765_sql_compatibility_aliases.sql
index 791231b9598..85b33efa485 100644
--- a/dbms/tests/queries/0_stateless/00765_sql_compatibility_aliases.sql
+++ b/dbms/tests/queries/0_stateless/00765_sql_compatibility_aliases.sql
@@ -6,3 +6,6 @@ select LOWER('Foo');
 select UPPER('Foo');
 select REPLACE('bar', 'r', 'z');
 select Locate('foo', 'o');
+select SUBSTRING('foo', 1, 2);
+select Substr('foo', 2);
+select mid('foo', 3);