如何從此表中檢索唯一記錄？

Question

我有兩個表：CardInfo和CardItems，所以每個CardInfo可能有多個CardItems。我需要一個SQL查詢來根據與CardInfo和CardItems表相關的一些條件從CardInfo獲取唯一記錄。

select c.* from CardInfo c, CardItems ci 
where c.cr_no = ci.cr_no and ci.wc_id = 'test' 

上面的查詢返回重複記錄。請提出解決方案。

Answer 1

您可以刪除重複記錄與DISTINCT

select distinct c.* from CardInfo c, CardItems ci 
where c.cr_no = ci.cr_no and ci.wc_id = 'test' 

Answer 2

select c.* from cardinfo as c innerjoin carditems as ci 
     on c.cr_no=ci.cr_no 
where ci.wc_id = 'test'