SQL存儲過程加入問題

Question

當前存儲過程根據作爲參數傳遞的employee_number返回一條記錄。如果surpervisor_id爲NULL，則不返回記錄。如果我想用所有其他字段返回記錄，並且在supervisor_id字段中有NULL，那麼我將如何配置該記錄？

SELECT DISTINCT 
    tblPeople.PERSON_ID, tblPeople.FIRST_NAME, tblPeople.LAST_NAME, 
    tblPeople.EMPLOYEE_NUMBER, tblPeople.EMAIL_ADDRESS, 
    tblAddress.ADDRESS_LINE1, tblAddress.ADDRESS_LINE2, tblAddress.ADDRESS_LINE3, 
    tblAddress.TOWN_OR_CITY, tblAddress.STATE, tblAddress.COUNTRY, 
    tblAddress.POSTAL_CODE, tblPeople.PHONE_NUMBER, 
    tblPeople.EFFECTIVE_START_DATE, tblPeople.EFFECTIVE_END_DATE, 
    tblLocation.LOC_CODE, 
    pp2.FIRST_NAME AS Expr1, pp2.LAST_NAME AS Expr2, 
    pp2.EMPLOYEE_NUMBER AS Expr3, tblAssignment.SUPERVISOR_ID, 
    tblAssignment.ATTRIBUTE2, tblAssignment.ATTRIBUTE3, 
    tblPeople.INSTANCE_ID, tblAssignment.LOC_ID 
FROM 
    tblPeople AS tblPeople 
RIGHT OUTER JOIN 
    tblAddress AS tblAddress ON tblPeople.PERSON_ID = tblAddress.PERSON_ID 
          AND tblPeople.INSTANCE_ID = tblAddress.INSTANCE_ID 
INNER JOIN 
    tblAssignments AS tblAssignment ON tblPeople.PERSON_ID = tblAssignment.PERSON_ID 
            AND tblPeople.INSTANCE_ID = tblAssignment.INSTANCE_ID 
INNER JOIN 
    Locations AS Location ON Location.LOC_ID = tblAssignment.LOC_ID 
          AND Location.INSTANCE_ID = tblAssignment.INSTANCE_ID 
INNER JOIN 
    tblPeople AS pp2 ON pp2.PERSON_ID = tblAssignment.SUPERVISOR_ID 
        AND pp2.INSTANCE_ID = tblAssignment.INSTANCE_ID 
WHERE  
    tblPeople.EMPLOYEE_NUMBER = '3298' 
    AND tblPeople.INSTANCE_ID = 1 
    AND tblAssignment.Assignment_Status = 'Current' 

Answer 1

最有可能的，你只需要改變這一JOIN

INNER JOIN 
    tblPeople AS pp2 ON pp2.PERSON_ID = tblAssignment.SUPERVISOR_ID 
        AND pp2.INSTANCE_ID = tblAssignment.INSTANCE_ID 

一個LEFT OUTER JOIN

LEFT OUTER JOIN 
    tblPeople AS pp2 ON pp2.PERSON_ID = tblAssignment.SUPERVISOR_ID 
        AND pp2.INSTANCE_ID = tblAssignment.INSTANCE_ID 

如果SUPERVISOR_ID IS NULL，然後從pp2表中的列會爲NULL，但您仍應該獲取其他所有列的數據。