举个例子
"select * from table1 limit 50"
"select * from table1 limit 50 100"
"select * from table2 where col in (select col from table2 limit 50) limit 100 200"
这几个字符串处理后没有变化
"select * from table1"
"select * from table1 where col='val'"
"select * from table2 where col in (select col from table2 limit 50)"
处理后分别是
"select * from table1 limit 10000"
"select * from table1 where col='val' limit 10000"
"select * from table2 where col in (select col from table2 limit 50) limit 10000"