当一个表对一个表具有FOREIGN KEY时，查询从3个表中选择数据

Question

1. 我有三张桌子（ASSETINFO，VENDORINFO，STATEINFO）

2. 我执行以下查询：

   SELECT t2.TYPE [TYPE], t3.Status [STATUS], t4.COMPANY, T5.STATEID [STATE] 
   
   FROM ASSETINFO t1 
   
   INNER Join TYPEINFO t2 on t1.TYPEID = t2.TYPEID
   INNER Join STATUSINFO t3 on t1.STATUSID = t3.STATUSID
   INNER Join VENDORINFO t4 on t1.VENDORID = t4.VENDORID 
   INNER Join VENDORINFO t5 on t1.VENDORID = t5.VENDORID 
   

并取回以下结果：

TYPE: NETWORK FIREWALL | STATUS: ASSIGNED | COMPANY: DELL  | STATE: 3

我可以从TABLE VENDORINFO中检索COMPANY名称但是，我不知道如何用STATE列中的值替换表STATEINFO中的STATEID？

Answer 1

您的vendorInfo的第二次加入不是必需的。而是加入您的Stateinfo表：

SELECT t2.TYPE [TYPE], t3.Status [STATUS], t4.COMPANY, T5.STATE 

FROM ASSETINFO t1 

INNER Join TYPEINFO t2 on t1.TYPEID = t2.TYPEID
INNER Join STATUSINFO t3 on t1.STATUSID = t3.STATUSID
INNER Join VENDORINFO t4 on t1.VENDORID = t4.VENDORID 
INNER Join stateINFO t5 on t4.State = t5.StateId

然后引入State