小编use*_*635的帖子

如何使用日期添加或日期差异功能我有一个场景,我需要找到生日是今天或n天后的人.我怎样才能在informix中实现它.

SELECT mbr_code, fname, lname
INTO rsMbrCode, rsFName, rsLName
FROM asamembr
WHERE cust_code = membershipnumber 
    AND ((day(bdate) - day(CURRENT)) <= rsTest 
    AND MONTH(bdate) = month(CURRENT))

RETURN rsMbrCode, rsFName, rsLName WITH RESUME;

我们有一个名为asamembr的表,其中包含两个字段:cust_code和mbrcode.

还有另一个表membermessage与外键具有相同的字段但是当我使用以下查询来创建约束时:

alter table 'informix'.messageclubmembership add constraint foreign key 
            (membership_number, member_code)
            references 'informix'.asamembr
            (cust_code, mbr_code) 
            on delete cascade 
            constraint fk_messageclubm926;

我收到此错误:

 Cannot find unique constraint or primary key on referenced table (informix.asamembr)

您能否告诉我如何在两个字段cust_code和mbr_code上查询表asamembr上是否存在主键？