刚刚开始用ddb，python代码，发现如下问题：

>>>q = table.where('S_INFO_WINDCODE like "%.S%"')

>>>q.showSQL()

'select OBJECT_ID,S_INFO_WINDCODE,TRADE_DT,......, from data_TMP_TBL_c6c09252 where S_INFO_WINDCODE like "%.S%"'

>>>q.select('*').showSQL()

'select * from data_TMP_TBL_c6c09252 where S_INFO_WINDCODE like "%.S%"'

>>>q.select('*').select('TRADE_DT').showSQL()

'select TRADE_DT from (select * from data_TMP_TBL_c6c09252 where S_INFO_WINDCODE like "%.S%") where S_INFO_WINDCODE like "%.S%"'

这里出现了两次where，直观的感觉，应该没有后面的一个where语句。这算是bug，还是语法特性？

如果想要实现没有后面的where应该怎么写？