SQL query, if value is null then return 1

2019-03-10 12:41发布

I have a query that is returning the exchange rate value set up in our system. Not every order will have an exchange rate (currate.currentrate) so it is returning null values.

Can I get it to return 1 instead of null?

Something like an if statement maybe:

 if isnull(currate.currentrate) then 1 else currate.currentrate 

Here is my query below. I greatly appreciate all your help!

 SELECT     orderhed.ordernum, orderhed.orderdate, currrate.currencycode,  currrate.currentrate
 FROM         orderhed LEFT OUTER JOIN
                  currrate ON orderhed.company = currrate.company AND orderhed.orderdate = currrate.effectivedate

标签: tsql null ssms
6条回答
【Aperson】
2楼-- · 2019-03-10 13:13

try like below...

CASE 
WHEN currate.currentrate is null THEN 1
ELSE currate.currentrate
END as currentrate
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放我归山
3楼-- · 2019-03-10 13:15

You can use COALESCE:

SELECT  orderhed.ordernum, 
    orderhed.orderdate, 
    currrate.currencycode,  
    coalesce(currrate.currentrate, 1) as currentrate
FROM orderhed 
LEFT OUTER JOIN currrate 
    ON orderhed.company = currrate.company 
    AND orderhed.orderdate = currrate.effectivedate

Or even IsNull():

SELECT  orderhed.ordernum, 
    orderhed.orderdate, 
    currrate.currencycode,  
    IsNull(currrate.currentrate, 1) as currentrate
FROM orderhed 
LEFT OUTER JOIN currrate 
    ON orderhed.company = currrate.company 
    AND orderhed.orderdate = currrate.effectivedate

Here is an article to help decide between COALESCE and IsNull:

http://www.mssqltips.com/sqlservertip/2689/deciding-between-coalesce-and-isnull-in-sql-server/

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老娘就宠你
4楼-- · 2019-03-10 13:24
SELECT orderhed.ordernum, orderhed.orderdate, currrate.currencycode,  

case(currrate.currentrate) when null then 1 else currrate.currentrate end

FROM orderhed LEFT OUTER JOIN currrate ON orderhed.company = currrate.company AND orderhed.orderdate = currrate.effectivedate  
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男人必须洒脱
5楼-- · 2019-03-10 13:27

a) If you want 0 when value is null

SELECT isnull(PartNum,0) AS PartNumber, PartID
FROM Part

b) If you want 0 when value is null and otherwise 1

SELECT 
  (CASE
    WHEN PartNum IS NULL THEN 0
    ELSE 1
  END) AS PartNumber,
  PartID
FROM Part
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Ridiculous、
6楼-- · 2019-03-10 13:28
SELECT 
    ISNULL(currate.currentrate, 1)  
FROM ...

is less verbose than the winning answer and does the same thing

https://msdn.microsoft.com/en-us/library/ms184325.aspx

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闹够了就滚
7楼-- · 2019-03-10 13:31

You can use a CASE statement.

SELECT 
    CASE WHEN currate.currentrate IS NULL THEN 1 ELSE currate.currentrate END
FROM ...
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