select d.故障范围 from 调度 a,机主 b,机28 c,故障 d where a.机车id=b.机车id and b.机28id=c.机28id and c.故障id=d.故障id and a.机车id=?(你要查询的值)
select 调度.机车id,故障.故障范围 from 调度,机主,机28,故障 where 调度.机车id=机主.机车id and 机主.机28id=机28.机28id and 机28.故障id=故障.故障范围
我还是不明白啊。象他所说的:select 调度.机车id,故障.故障范围 from 调度,机主,机28,故障 where 调度.机车id=机主.机车id and 机主.机28id=机28.机28id and 机28.故障id=故障.故障范围 最终我查出来的是什么呢?我想取这个“故障范围”的值。怎么取呢? 换句话说我还想判断一下这个值是否在AA中。怎么实现呢?
select d.故障范围 from 调度 a,机主 b,机28 c,故障 d where a.机车id=b.机车id and b.机28id=c.机28id and c.故障id=d.故障id and a.机车id=?(你要查询的值) label1.caption:=adoquery1.fieldbyname('故障范围').asstring 即可
SELECT dbo.调度.机车ID, dbo.故障.故障范围 FROM dbo.调度 INNER JOIN dbo.机主 ON dbo.调度.机车ID = dbo.机主.机车id INNER JOIN dbo.机28 ON dbo.机主.机28id = dbo.机28.机28id INNER JOIN dbo.故障 ON dbo.机28.故障id = dbo.故障.故障id
select d.故障范围,d.时间 from 调度 a,机主 b,机28 c,故障 d where a.机车id=b.机车id and b.机28id=c.机28id and c.故障id=d.故障id and a.机车id=:varid //varid为查询参数 label1.caption:=adoquery1.fieldbyname('故障范围').asstring; label2.caption:=datetimetostr(adoquery1.fieldbyname('时间').asdatetime);
调度有:机车id
机主有:机车id 机28id
机28有:机28id 故障id
故障有:故障id,故障范围
我想通过调度表里的‘机车id’查出来故障表里的‘故障范围’记录具体要怎么做呢?
where a.机车id=b.机车id and b.机28id=c.机28id and c.故障id=d.故障id
and a.机车id=?(你要查询的值)
from 调度,机主,机28,故障
where 调度.机车id=机主.机车id and 机主.机28id=机28.机28id
and 机28.故障id=故障.故障范围
from 调度,机主,机28,故障
where 调度.机车id=机主.机车id and 机主.机28id=机28.机28id
and 机28.故障id=故障.故障范围
最终我查出来的是什么呢?我想取这个“故障范围”的值。怎么取呢?
换句话说我还想判断一下这个值是否在AA中。怎么实现呢?
同样。在这个表里还有时间字段。我要把查出来的故障范围对应的记录一起的时间也显示出来~!
ADOOBJECT。Fields(“FieldsName”)
where a.机车id=b.机车id and b.机28id=c.机28id and c.故障id=d.故障id
and a.机车id=?(你要查询的值)
label1.caption:=adoquery1.fieldbyname('故障范围').asstring
即可
FROM dbo.调度 INNER JOIN
dbo.机主 ON dbo.调度.机车ID = dbo.机主.机车id INNER JOIN
dbo.机28 ON dbo.机主.机28id = dbo.机28.机28id INNER JOIN
dbo.故障 ON dbo.机28.故障id = dbo.故障.故障id
where a.机车id=b.机车id and b.机28id=c.机28id and c.故障id=d.故障id
and a.机车id=:varid //varid为查询参数
label1.caption:=adoquery1.fieldbyname('故障范围').asstring;
label2.caption:=datetimetostr(adoquery1.fieldbyname('时间').asdatetime);