Handle blank SQL when parsing table name (#1210)

lib/active_record/connection_adapters/sqlserver/schema_statements.rb

@@ -673,6 +673,8 @@ def get_table_name(sql)
 
         # Parses the raw table name that is used in the SQL. Table name could include database/schema/etc.
         def get_raw_table_name(sql)
+          return if sql.blank?
+
           s = sql.gsub(/^\s*EXEC sp_executesql N'/i, "")
 
           if s.match?(/^\s*INSERT INTO.*/i)

test/cases/schema_test_sqlserver.rb

@@ -66,6 +66,10 @@ class SchemaTestSQLServer < ActiveRecord::TestCase
       it do
         assert_equal "[WITH - SPACES$DOLLAR]", connection.send(:get_raw_table_name, "SELECT id FROM [WITH - SPACES$DOLLAR]")
       end
+
+      it do
+        assert_nil connection.send(:get_raw_table_name, nil)
+      end
     end
 
     describe 'INSERT statements' do