55

I have a select statement which will return 2 columns.

ID | IDParent

Then in my program I have to test if IDParent is < 1 then use ID ELSE use IDParent

Is there a way to use an If Else like condition in SQL to return only single value?

Ian
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user160820
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11 Answers11

114

you can use CASE

SELECT   ...,
         CASE WHEN IDParent < 1 THEN ID ELSE IDPArent END AS ColumnName,
         ...
FROM     tableName
John Woo
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34

Here, using CASE Statement and find result:

select (case when condition1 then result1
             when condition2 then result2
             else result3
             end) as columnname from tablenmae:

For example:

select (CASE WHEN IDParent< 1 then ID 
             else IDParent END) as columnname
from tablenmae
Chris Martin
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Vikram Jain
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23
SELECT CASE WHEN IDParent < 1 
            THEN ID 
            ELSE IDParent 
       END AS colname 
FROM yourtable
AnandPhadke
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7

Here are two ways "IF" Or "CASE".

SELECT IF(COLUMN_NAME = "VALUE", "VALUE_1", "VALUE_2") AS COLUMN_NAME 
FROM TABLE_NAME;

OR

SELECT (CASE WHEN COLUMN_NAME = "VALUE" THEN 'VALUE_1' ELSE 'VALUE_2' END) AS COLUMN_NAME 
FROM TABLE_NAME;
Kennedy Maikuma
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M. Hamza Rajput
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4

The query will be like follows

SELECT (CASE WHEN tuLieuSo is null or tuLieuSo=''
            THEN 'Chưa có đĩa' 
            ELSE 'Có đĩa' End) AS tuLieuSo,moTa
FROM [gPlan_datav3_SQHKTHN].[dbo].[gPlan_HoSo]
sugunan
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user4112005
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3

sql server 2012

  with
  student as 
(select sid,year from (
values (101,5),(102,5),(103,4),(104,3),(105,2),(106,1),(107,4)
) as student(sid,year)
)
select iif(year=5,sid,year) as myCol,* from student


 myCol  sid year
101 101 5
102 102 5
4   103 4
3   104 3
2   105 2
1   106 1
4   107 4
user3380585
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3

Here is some example using CASE WHEN

SELECT 
    CASE WHEN A > 1 THEN
            'Greater than 1'
    END  
FROM TRIANGLES

.

SELECT 
    CASE WHEN A > 1 THEN
            A
    END  
FROM TRIANGLES

.

SELECT 
    CASE WHEN A > 1 and B > 1 THEN
            'Greater than 1'
    END  
FROM TRIANGLES

.

SELECT 
    CASE WHEN A > 1 THEN
            'greater than 1'
         ELSE
            'less than 1'
    END  
FROM TRIANGLES

.

SELECT 
    CASE WHEN A > 1 THEN
            'greater than 1'
         ELSE CASE WHEN A >= 0 THEN
                      'greater than or equal 0'
                   ELSE
                      'less than 0'
              END        
    END  
FROM TRIANGLES;

Hope this helps

Varun
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Linh
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2

You can use simply if statement under select query as like I have described below

if(some_condition,if_satisfied,not_satisfied)

SELECT IF(IDParent < 1,ID,IDParent)  FROM yourTable ;
barbsan
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Rohit Mewada
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    You propably meant [IIF](https://learn.microsoft.com/en-us/sql/t-sql/functions/logical-functions-iif-transact-sql) – barbsan Apr 17 '19 at 09:50
0

You can also use a union construct. I'm not sure if CASE is a common SQL construct ...

SELECT ID FROM tabName WHERE IDParent<1 OR IDParent IS NULL
UNION 
SELECT IDParent FROM tabName WHERE IDParent>1
OkieOth
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0
select 
CASE WHEN IDParent is < 1 then ID else IDParent END as colname 
from yourtable
Nirav Ranpara
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0

I Have a Query With This result : 

SELECT Top 3
 id,
 Paytype
 FROM dbo.OrderExpresses
 WHERE CreateDate > '2018-04-08'

The Result is : 

22082   1
22083   2
22084   1

I Want Change The Code To String In Query, So I Use This Code : 

SELECT TOP 3
 id,
 CASE WHEN Paytype = 1 THEN N'Credit' ELSE N'Cash' END AS PayTypeString
 FROM dbo.OrderExpresses
 WHERE CreateDate > '2018-04-08'

And Result Is :)

22082   Credit
22083   Cash
22084   Credit
Davoud Gharajeh
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