[英]Why does my output on sqlite inner join multiplies?
I have 2 tables.. 我有2张桌子。
I will represent the data inn array.... 我将代表数据旅馆数组。
table1
columns are t1_id, t1_value
table1
列是t1_id, t1_value
table2
columns are t2_id, t2_value, t1_id(FK)
table2
列是t2_id, t2_value, t1_id(FK)
table1={{1,data1},{2,data2}};
table2={{1,d1,t1.1},{2,d2,t1.1},{3,d3,t1.2},{4,d4,t1.2}};
i have a query of.. 我有一个查询。
rs = stmt.executeQuery("SELECT t2_value FROM table2 INNER JOIN table1
ON table2.t1_id=(SELECT t1_id FROM table1 WHERE t1_value='my_value');")
I got the right value i needed but instead of just.. 我得到了我需要的正确的价值,而不仅仅是..
d1
d2
what I got is.. 我得到的是..
d1
d2
d1
d2
Please help! 请帮忙!
Why not try this: 为什么不试试这个:
SELECT t2_value FROM table2 INNER JOIN table1 ON table2.t1_id=table1.t1_id WHERE table1.t1_value='my_value
' SELECT t2_value FROM table2 INNER JOIN table1 ON table2.t1_id=table1.t1_id WHERE table1.t1_value='my_value
'
SELECT table2.t2_value FROM table2
INNER JOIN table1 ON table2.t1_id = table1.t1_id
WHERE table1.t1_value='my_value'
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.