已知父表的字段对这个表的子表的某一个字段求和

SELECT SW_JOURNAL_NUMBER,SW_ID,SW_TO_ID,CI_NAME,CI_LINKMAN,CI_TEL,CI_TEL,CI_MOBILE,
(SELECT SUM(WG_AMOUNT) FROM dbo.SBD_WAYBILL_GOODS WHERE WG_SW_ID=SW_ID GROUP BY WG_SW_ID) AS SW_AMOUNT,
SW_STATUS
FROM dbo.SBD_WAYBILL w
LEFT JOIN dbo.SBD_ASSEMBLYBILL_WAYBILL aw ON w.SW_ID =aw.AW_SW_ID
LEFT JOIN dbo.SBD_ASSEMBLY_BILL ab ON aw.AW_AB_ID=ab.AB_ID
LEFT JOIN dbo.SBD_CUSTOMER_INFO ci ON w.SW_TO_ID=ci.CI_ID

WHERE AB_ID=173