diff --git a/phpBB/includes/db/dbal.php b/phpBB/includes/db/dbal.php
index 358df50402..9cc337955b 100644
--- a/phpBB/includes/db/dbal.php
+++ b/phpBB/includes/db/dbal.php
@@ -500,6 +500,18 @@ class dbal
 		return $column_name . ' | ' . (1 << $bit) . (($compare) ? ' ' . $compare : '');
 	}
 
+	/**
+	* Run LOWER() on DB column of type text (i.e. neither varchar nor char).
+	*
+	* @param string $column_name	The column name to use
+	*
+	* @return string				A SQL statement like "LOWER($column_name)"
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER($column_name)";
+	}
+
 	/**
 	* Run more than one insert statement.
 	*
diff --git a/phpBB/includes/db/mssql.php b/phpBB/includes/db/mssql.php
index 6899a73902..b7178593dc 100644
--- a/phpBB/includes/db/mssql.php
+++ b/phpBB/includes/db/mssql.php
@@ -332,6 +332,14 @@ class dbal_mssql extends dbal
 		return str_replace(array("'", "\0"), array("''", ''), $msg);
 	}
 
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER(SUBSTRING($column_name, 1, DATALENGTH($column_name)))";
+	}
+
 	/**
 	* Build LIKE expression
 	* @access private
diff --git a/phpBB/includes/db/mssql_odbc.php b/phpBB/includes/db/mssql_odbc.php
index 34f7a87337..2ecc42cadf 100644
--- a/phpBB/includes/db/mssql_odbc.php
+++ b/phpBB/includes/db/mssql_odbc.php
@@ -310,6 +310,14 @@ class dbal_mssql_odbc extends dbal
 		return str_replace(array("'", "\0"), array("''", ''), $msg);
 	}
 
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER(SUBSTRING($column_name, 1, DATALENGTH($column_name)))";
+	}
+
 	/**
 	* Build LIKE expression
 	* @access private
diff --git a/phpBB/includes/db/mssqlnative.php b/phpBB/includes/db/mssqlnative.php
index 92ac9b1fb9..c91cc188b0 100644
--- a/phpBB/includes/db/mssqlnative.php
+++ b/phpBB/includes/db/mssqlnative.php
@@ -492,6 +492,14 @@ class dbal_mssqlnative extends dbal
 		return str_replace(array("'", "\0"), array("''", ''), $msg);
 	}
 
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER(SUBSTRING($column_name, 1, DATALENGTH($column_name)))";
+	}
+
 	/**
 	* Build LIKE expression
 	* @access private