我想检查数据，但如果它为空或空忽略它。目前查询如下…
Select
Coalesce(listing.OfferText, company.OfferText, '') As Offer_Text,
from tbl_directorylisting listing
Inner Join tbl_companymaster company
On listing.company_id= company.company_id
但我想找个伴。OfferText如果列表。Offertext是一个空字符串，如果它是null。
最好的解决方案是什么?
当前回答
您可以使用ISNULL并根据已知输出检查答案:
SELECT case when ISNULL(col1, '') = '' then '' else col1 END AS COL1 FROM TEST
其他回答
这里有另一个解决方案:
SELECT Isnull(Nullif(listing.offertext, ''), company.offertext) AS offer_text,
FROM tbl_directorylisting listing
INNER JOIN tbl_companymaster company
ON listing.company_id = company.company_id
防止SQL结果中出现空值或空值的记录
我们可以简单地添加.....WHERE Column_name != "或'null'
这里有一个解决方案，但我不知道它是否是最好的....
Select
Coalesce(Case When Len(listing.Offer_Text) = 0 Then Null Else listing.Offer_Text End, company.Offer_Text, '') As Offer_Text,
from tbl_directorylisting listing
Inner Join tbl_companymaster company
On listing.company_id= company.company_id
[Column_name] IS NULL OR LEN(RTRIM(LTRIM([Column_name]))) = 0
我认为:
SELECT
ISNULL(NULLIF(listing.Offer_Text, ''), company.Offer_Text) AS Offer_Text
FROM ...
是最优雅的解决方案。
然后把它分解成伪代码:
// a) NULLIF:
if (listing.Offer_Text == '')
temp := null;
else
temp := listing.Offer_Text; // may now be null or non-null, but not ''
// b) ISNULL:
if (temp is null)
result := true;
else
result := false;
