如何使用case语句检查列是否为空
如何使用case语句检查列是否为空
提问于 2013-10-01 08:03:20
我必须使用3个表创建一个存储过程，第一个是登记表、求职者表、就业明细表。因为我现在在前两个tables.Till中有条目，所以在就业明细表中没有任何条目。
我有以下问题：
select RD.FirstName,RD.LastName,
(select case when JR.profileHeadline=''
then 'No Resume Headline mentioned'
else JR.profileHeadline end
from jobseekerReg JR)as profileHeadline ,
(select case when ED.designation=''
then 'No designation mentioned'
else ED.designation end
from employmentDetail ED)as designation,
(select case when ED.companyName=''
then 'No company name mentioned'
else ED.companyName end
from employmentDetail ED) as companyName,JR.location,
(select case when ED.funcArea=''
then 'No functional area mentioned'
else ED.funcArea end
from employmentDetail ED) as funcArea ,
(select case when ED.cmpIndustry=''
then 'No industry mentioned'
else ED.cmpIndustry end
from employmentDetail ED)as cmpIndustry,RD.BirthDay,
RD.Gender,JR.experience,
(select case when ED.salary=''
then 'No salary mentioned'
else ED.salary end
from employmentDetail ED)as salary ,JR.mobileNumber,JR.emailId,
JR.altEmailID,JR.jobSeekerAddrs,JR.maritalStatus,
(select case when JR.keySkills=''
then 'No keyskills mentioned'
else JR.keySkills end
from jobseekerReg JR)as keySkills
from RegistrationDetails RD join jobseekerReg JR on RD.Reg_Id=JR.regId
left outer join employmentDetail ED on ED.regId=JR.regId
and ED.regId=2 where RD.Reg_Id=JR.regId and RD.Reg_Id=2 and JR.regId=2上面的查询提供了正确的输出，但问题是，由于regId=2的就业表中没有任何条目，因此该表中的列将输出作为null。我该如何处理这个问题？请提前给我任何解决方案谢谢。
回答 1
Stack Overflow用户
回答已采纳
发布于 2013-10-01 08:18:49
CASE WHEN ED.Salary IS NULL THEN 'No salary mentioned' ELSE ED.Salary END但我认为就你的情况而言，ISNULL()会更好：
select RD.FirstName,RD.LastName,
ISNULL(JR.profileHeadline, 'No Resume Headline mentioned') as profileHeadline ,
ISNULL(ED.designation, 'No designation mentioned') as designation,
ISNULL(ED.companyName, 'No company name mentioned') as companyName,
JR.location,
ISNULL(ED.funcArea, 'No functional area mentioned') as funcArea ,
ISNULL(ED.cmpIndustry, 'No industry mentioned') as cmpIndustry,
RD.BirthDay,
RD.Gender, JR.experience,
ISNULL(ED.salary, 'No salary mentioned' as salary ,
JR.mobileNumber,JR.emailId,
JR.altEmailID,JR.jobSeekerAddrs,JR.maritalStatus,
ISNULL(JR.keySkills, 'No keyskills mentioned') as keySkills
from RegistrationDetails RD join jobseekerReg JR on RD.Reg_Id=JR.regId
left outer join employmentDetail ED on ED.regId=JR.regId
and ED.regId=2 where RD.Reg_Id=JR.regId and RD.Reg_Id=2 and JR.regId=2页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/19110982
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