解决MySQL查询limit改写时，SQL语句中更小的limit值被覆盖的问题

hhyo · Jul 27, 2019 · a345f51 · a345f51
1 parent 6077f53
commit a345f51
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diff --git a/sql/engines/mysql.py b/sql/engines/mysql.py
@@ -150,8 +150,12 @@ def filter_sql(self, sql='', limit_num=0):
             # LIMIT N, N 或LIMIT N OFFSET N
             limit_offset = re.compile(r'limit([\s]*\d+[\s]*)(,|offset)([\s]*\d+[\s]*)$', re.I)
             if limit_n.search(sql):
+                sql_limit = limit_n.search(sql).group(1)
+                limit_num = min(int(limit_num), int(sql_limit))
                 sql = limit_n.sub(f'limit {limit_num};', sql)
             elif limit_offset.search(sql):
+                sql_limit = limit_offset.search(sql).group(3)
+                limit_num = min(int(limit_num), int(sql_limit))
                 sql = limit_offset.sub(f'limit {limit_num};', sql)
             else:
                 sql = f'{sql} limit {limit_num};'

diff --git a/sql/engines/tests.py b/sql/engines/tests.py
@@ -343,6 +343,12 @@ def test_filter_sql_with_limit(self):
         check_result = new_engine.filter_sql(sql=sql_without_limit, limit_num=1)
         self.assertEqual(check_result, 'select user from usertable limit 1;')
 
+    def test_filter_sql_with_limit_min(self):
+        new_engine = MysqlEngine(instance=self.ins1)
+        sql_without_limit = 'select user from usertable limit 10'
+        check_result = new_engine.filter_sql(sql=sql_without_limit, limit_num=100)
+        self.assertEqual(check_result, 'select user from usertable limit 10;')
+
     def test_filter_sql_with_limit_offset(self):
         new_engine = MysqlEngine(instance=self.ins1)
         sql_without_limit = 'select user from usertable limit 10 offset 100'