From 9d0c600d8d6359107cdbef5f0c30757321da09f6 Mon Sep 17 00:00:00 2001
From: Adam Chainz <adam@adamj.eu>
Date: Wed, 8 Apr 2015 22:26:09 +0100
Subject: [PATCH] Fixed #24609 -- Made ConcatPair use CONCAT_WS() on MySQL

---
 django/db/models/functions.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/django/db/models/functions.py b/django/db/models/functions.py
index 610ecb6985..613d396093 100644
--- a/django/db/models/functions.py
+++ b/django/db/models/functions.py
@@ -47,7 +47,9 @@ class ConcatPair(Func):
         return super(ConcatPair, self).as_sql(compiler, connection)
 
     def as_mysql(self, compiler, connection):
-        self.coalesce()
+        # Use CONCAT_WS with an empty separator so that NULLs are ignored.
+        self.function = 'CONCAT_WS'
+        self.template = "%(function)s('', %(expressions)s)"
         return super(ConcatPair, self).as_sql(compiler, connection)
 
     def coalesce(self):