select distinct fb_mamodel from tblb_machine where fb_macode in(select distinct fb_macode from tblb_matoba where fbatterycode='$fbatterycode') and fclasscode='1' and fb_mabrand='$fb_babrand'"distinct : 使记录不重复查询 fb_macode 等于子查询 (select distinct fb_macode from tblb_matoba where fbatterycode='$fbatterycode')
并且满足 fclasscode='1' and fb_mabrand='$fb_babrand'
并且满足 fclasscode='1' and fb_mabrand='$fb_babrand'
1)值的范围在是在tblb_matoba表里并且 fbatterycode='$fbatterycode'(子查询)
2) fclasscode='1' and fb_mabrand='$fb_babrand'"