thinphp 中怎么写子查询跟UNION

select a.dept_id , a.ti_code , a.ti_date , a.Status , a.item_code , a.item_name_cn , a.OEMCode , a.carMod, a.unit , a.In_Qty , a.po_code , a.confirmedOn , b.carcatname , b.propyear , b.proplabel , b.cat1
from (
SELECT stock_ti_master.dept_id,

stock_ti_master.ti_code,

stock_ti_master.ti_date,

stock_ti_master.Status,

stock_ti_detail.item_code,

stock_ti_detail.item_name_cn,

stock_ti_detail.OEMCode,

stock_ti_detail.carMod,

stock_ti_detail.unit,

stock_ti_detail.In_Qty,

stock_ti_master.po_code,

purchase_po_master.confirmedOn
FROM stock_ti_detail left join stock_ti_master LEFT OUTER JOIN purchase_po_master ON stock_ti_master.po_dept = purchase_po_master.dept_id AND stock_ti_master.po_code = purchase_po_master.PO_code on ( stock_ti_detail.dept_id = stock_ti_master.dept_id ) and ( stock_ti_detail.ti_code = stock_ti_master.ti_code )
UNION ALL
SELECT stock_supplyin_master.dept_id,

stock_supplyin_master.supplyin_code,

stock_supplyin_master.supplyin_date,

stock_supplyin_master.Status,

stock_supplyin_detail.item_code,

stock_supplyin_detail.item_name_cn,

stock_supplyin_detail.OEMCode,

stock_supplyin_detail.carMod,

stock_supplyin_detail.unit,

stock_supplyin_detail.item_qty,

stock_supplyin_master.supplyto_code,

stock_supplyto_master.confirmon

FROM stock_supplyin_detail left join stock_supplyin_master LEFT OUTER JOIN stock_supplyto_master ON stock_supplyin_master.from_dept = stock_supplyto_master.dept_id AND stock_supplyin_master.supplyto_code = stock_supplyto_master.supplyto_code on ( stock_supplyin_detail.dept_id = stock_supplyin_master.dept_id ) and ( stock_supplyin_detail.supplyin_code = stock_supplyin_master.supplyin_code ) ) A left join basic_item b on a.item_code = b.item_code
用tp的链式写法要怎么写这条Sql

https://blog.csdn.net/u014508939/article/details/78094614