如何在條件鏈接到第三個表的情況下聯接兩個表

Question

我有3張桌子

Table1 : ID, Description
Table2 : ID, FirstName, LastName
Table3 : FirstName, LastName, Flag 

我想保留鏈接到第三個表的條件加入table1和table2。

Result Table: ID, Description, FullName (FirstName + LastName) 
(Condition: only the names that have flag set to true in table3 can be used in the resultant table)

我如何完成以下工作？ 先感謝您。

Answer 1

SELECT t1.ID, t1.Description, t2.FirstName + ' ' + t2.LastName as FullName
FROM Table1 t1
JOIN Table2 t2 ON t1.ID = t2.ID
JOIN Table3 t3 ON t2.FirstName=t3.FirstName AND t2.LastName=t3.LastName
WHERE t3.Flag=1