Question

我被困在一个查询中，我想显示来自不同表及其桥表的数据表格是：

bridge (bid,planid,fbridgeid)
fbridge (fbridgeid,featureid,valueid)
features (featureid,fname)
value (valueid,value)
plans (planid,name,price,discount)

以下是我的查询：

SELECT 
(NAME AS pname, price AS prize,
 discount AS ds, fname AS feature, VALUE AS vlue 
FROM plans  )

我想从数据库中获取所有列，但是根据计划

like planid 1 ->> contains ->> feature id 1,2,3 and valueid 1,3,5 etc )

Answer 1

Join将是：

SELECT pl.name AS pname, pl.price AS prize , pl.discount AS ds , fe.fname AS feature, va.VALUE AS vlue
FROM plans pl
JOIN bridge br ON br.planid = pl.planid
JOIN fbridge fb ON fb.fbridgeid = br.fbridgeid
JOIN features fe ON fe.featureid = fb.featureid
JOIN value va ON va.valueid = fb.valueid
WHERE pl.plainid = 1

Answer 2

将表格加入正确的字段。

SELECT *
FROM plans p
INNER JOIN bridge b ON p.planid = b.planid
INNER JOIN fbridge fb ON b.fbridgeid = fb.fbridgeid
INNER JOIN features f ON fb.featureid = f.featureid
INNER JOIN value v ON fb.valueid = v.valueid

然后您可以从中选择所有字段。

SELECT p.name AS pname, p.price AS prize, p.discount AS ds, f.fname AS feature, v.value AS vlue
FROM plans p
INNER JOIN bridge b ON p.planid = b.planid
INNER JOIN fbridge fb ON b.fbridgeid = fb.fbridgeid
INNER JOIN features f ON fb.featureid = f.featureid
INNER JOIN value v ON fb.valueid = v.valueid

Answer 3

select b.bid,b.planid,b.fbridgeid,fb.fbridgeid,f.featureid,f.fname,v.valueid,v.value,p.name,p.price,p.discount from bridge as b 
inner join fbridge as fb on fb.bridgeid=b.bridgeid 
inner join features as f on f.featureId=fb.featureid 
inner join value as v on v.valueid=fb.valueid 
inner join plans as p on p.planid=b.planid 
where p.planid=1 and f.featureId in (1,2,3) and v.valueid in (1,3,5)

sql join需要进一步帮助

3 个答案: