How do I perform an IF...THEN in an SQL SELECT?
SqlSql ServerTsqlIf StatementCaseSql Problem Overview
How do I perform an IF...THEN in an SQL SELECT statement?
For example:
SELECT IF(Obsolete = 'N' OR InStock = 'Y' ? 1 : 0) AS Saleable, * FROM Product
Sql Solutions
Solution 1 - Sql
The CASE statement is the closest to IF in SQL and is supported on all versions of SQL Server.
SELECT CAST(
CASE
WHEN Obsolete = 'N' or InStock = 'Y'
THEN 1
ELSE 0
END AS bit) as Saleable, *
FROM Product
You only need to use the CAST operator if you want the result as a Boolean value. If you are happy with an int, this works:
SELECT CASE
WHEN Obsolete = 'N' or InStock = 'Y'
THEN 1
ELSE 0
END as Saleable, *
FROM Product
CASE statements can be embedded in other CASE statements and even included in aggregates.
SQL Server Denali (SQL Server 2012) adds the IIF statement which is also available in access (pointed out by Martin Smith):
SELECT IIF(Obsolete = 'N' or InStock = 'Y', 1, 0) as Saleable, * FROM Product
Solution 2 - Sql
The case statement is your friend in this situation, and takes one of two forms:
The simple case:
SELECT CASE <variable> WHEN <value> THEN <returnvalue>
WHEN <othervalue> THEN <returnthis>
ELSE <returndefaultcase>
END AS <newcolumnname>
FROM <table>
The extended case:
SELECT CASE WHEN <test> THEN <returnvalue>
WHEN <othertest> THEN <returnthis>
ELSE <returndefaultcase>
END AS <newcolumnname>
FROM <table>
You can even put case statements in an order by clause for really fancy ordering.
Solution 3 - Sql
From SQL Server 2012 you can use the IIF function for this.
SELECT IIF(Obsolete = 'N' OR InStock = 'Y', 1, 0) AS Salable, *
FROM Product
This is effectively just a shorthand (albeit not standard SQL) way of writing CASE.
I prefer the conciseness when compared with the expanded CASE version.
Both IIF() and CASE resolve as expressions within a SQL statement and can only be used in well-defined places.
> The CASE expression cannot be used to control the flow of execution of > Transact-SQL statements, statement blocks, user-defined functions, and > stored procedures.
If your needs can not be satisfied by these limitations (for example, a need to return differently shaped result sets dependent on some condition) then SQL Server does also have a procedural IF keyword.
IF @IncludeExtendedInformation = 1
BEGIN
SELECT A,B,C,X,Y,Z
FROM T
END
ELSE
BEGIN
SELECT A,B,C
FROM T
END
Care must sometimes be taken to avoid parameter sniffing issues with this approach however.
Solution 4 - Sql
You can find some nice examples in The Power of SQL CASE Statements, and I think the statement that you can use will be something like this (from 4guysfromrolla):
SELECT
FirstName, LastName,
Salary, DOB,
CASE Gender
WHEN 'M' THEN 'Male'
WHEN 'F' THEN 'Female'
END
FROM Employees
Solution 5 - Sql
Use CASE. Something like this.
SELECT Salable =
CASE Obsolete
WHEN 'N' THEN 1
ELSE 0
END
Solution 6 - Sql
SELECT
(CASE
WHEN (Obsolete = 'N' OR InStock = 'Y') THEN 'YES'
ELSE 'NO'
END) as Salable
, *
FROM Product
Solution 7 - Sql
Microsoft SQL Server (T-SQL)
In a select, use:
select case when Obsolete = 'N' or InStock = 'Y' then 'YES' else 'NO' end
In a where clause, use:
where 1 = case when Obsolete = 'N' or InStock = 'Y' then 1 else 0 end
Solution 8 - Sql
From this link, we can understand IF THEN ELSE in T-SQL:
IF EXISTS(SELECT *
FROM Northwind.dbo.Customers
WHERE CustomerId = 'ALFKI')
PRINT 'Need to update Customer Record ALFKI'
ELSE
PRINT 'Need to add Customer Record ALFKI'
IF EXISTS(SELECT *
FROM Northwind.dbo.Customers
WHERE CustomerId = 'LARSE')
PRINT 'Need to update Customer Record LARSE'
ELSE
PRINT 'Need to add Customer Record LARSE'
Isn't this good enough for T-SQL?
Solution 9 - Sql
SELECT
CASE
WHEN OBSOLETE = 'N' or InStock = 'Y' THEN 'TRUE'
ELSE 'FALSE'
END AS Salable,
*
FROM PRODUCT
Solution 10 - Sql
Simple if-else statement in SQL Server:
DECLARE @val INT;
SET @val = 15;
IF @val < 25
PRINT 'Hi Ravi Anand';
ELSE
PRINT 'By Ravi Anand.';
GO
Nested If...else statement in SQL Server -
DECLARE @val INT;
SET @val = 15;
IF @val < 25
PRINT 'Hi Ravi Anand.';
ELSE
BEGIN
IF @val < 50
PRINT 'what''s up?';
ELSE
PRINT 'Bye Ravi Anand.';
END;
GO
Solution 11 - Sql
Use a CASE statement:
SELECT CASE
WHEN (Obsolete = 'N' OR InStock = 'Y')
THEN 'Y'
ELSE 'N'
END as Available
etc...
Solution 12 - Sql
A new feature, IIF (that we can simply use), was added in SQL Server 2012:
SELECT IIF ( (Obsolete = 'N' OR InStock = 'Y'), 1, 0) AS Saleable, * FROM Product
Solution 13 - Sql
Use pure bit logic:
DECLARE @Product TABLE (
id INT PRIMARY KEY IDENTITY NOT NULL
,Obsolote CHAR(1)
,Instock CHAR(1)
)
INSERT INTO @Product ([Obsolote], [Instock])
VALUES ('N', 'N'), ('N', 'Y'), ('Y', 'Y'), ('Y', 'N')
;
WITH cte
AS
(
SELECT
'CheckIfInstock' = CAST(ISNULL(NULLIF(ISNULL(NULLIF(p.[Instock], 'Y'), 1), 'N'), 0) AS BIT)
,'CheckIfObsolote' = CAST(ISNULL(NULLIF(ISNULL(NULLIF(p.[Obsolote], 'N'), 0), 'Y'), 1) AS BIT)
,*
FROM
@Product AS p
)
SELECT
'Salable' = c.[CheckIfInstock] & ~c.[CheckIfObsolote]
,*
FROM
[cte] c
See working demo: if then without case in SQL Server.
For start, you need to work out the value of true and false for selected conditions. Here comes two NULLIF:
for true: ISNULL(NULLIF(p.[Instock], 'Y'), 1)
for false: ISNULL(NULLIF(p.[Instock], 'N'), 0)
combined together gives 1 or 0. Next use bitwise operators.
It's the most WYSIWYG method.
Solution 14 - Sql
SELECT 1 AS Saleable, *
FROM @Product
WHERE ( Obsolete = 'N' OR InStock = 'Y' )
UNION
SELECT 0 AS Saleable, *
FROM @Product
WHERE NOT ( Obsolete = 'N' OR InStock = 'Y' )
Solution 15 - Sql
SELECT CASE WHEN profile.nrefillno = 0 THEN 'N' ELSE 'R'END as newref
From profile
Solution 16 - Sql
case statement some what similar to if in SQL server
SELECT CASE
WHEN Obsolete = 'N' or InStock = 'Y'
THEN 1
ELSE 0
END as Saleable, *
FROM Product
Solution 17 - Sql
This isn't an answer, just an example of a CASE statement in use where I work. It has a nested CASE statement. Now you know why my eyes are crossed.
CASE orweb2.dbo.Inventory.RegulatingAgencyName
WHEN 'Region 1'
THEN orweb2.dbo.CountyStateAgContactInfo.ContactState
WHEN 'Region 2'
THEN orweb2.dbo.CountyStateAgContactInfo.ContactState
WHEN 'Region 3'
THEN orweb2.dbo.CountyStateAgContactInfo.ContactState
WHEN 'DEPT OF AGRICULTURE'
THEN orweb2.dbo.CountyStateAgContactInfo.ContactAg
ELSE (
CASE orweb2.dbo.CountyStateAgContactInfo.IsContract
WHEN 1
THEN orweb2.dbo.CountyStateAgContactInfo.ContactCounty
ELSE orweb2.dbo.CountyStateAgContactInfo.ContactState
END
)
END AS [County Contact Name]
Solution 18 - Sql
If you're inserting results into a table for the first time, rather than transferring results from one table to another, this works in Oracle 11.2g:
INSERT INTO customers (last_name, first_name, city)
SELECT 'Doe', 'John', 'Chicago' FROM dual
WHERE NOT EXISTS
(SELECT '1' from customers
where last_name = 'Doe'
and first_name = 'John'
and city = 'Chicago');
Solution 19 - Sql
As an alternative solution to the CASE statement, a table-driven approach can be used:
DECLARE @Product TABLE (ID INT, Obsolete VARCHAR(10), InStock VARCHAR(10))
INSERT INTO @Product VALUES
(1,'N','Y'),
(2,'A','B'),
(3,'N','B'),
(4,'A','Y')
SELECT P.* , ISNULL(Stmt.Saleable,0) Saleable
FROM
@Product P
LEFT JOIN
( VALUES
( 'N', 'Y', 1 )
) Stmt (Obsolete, InStock, Saleable)
ON P.InStock = Stmt.InStock OR P.Obsolete = Stmt.Obsolete
Result:
ID Obsolete InStock Saleable
----------- ---------- ---------- -----------
1 N Y 1
2 A B 0
3 N B 1
4 A Y 1
Solution 20 - Sql
SELECT CASE WHEN Obsolete = 'N' or InStock = 'Y' THEN 1 ELSE 0
END AS Saleable, *
FROM Product
Solution 21 - Sql
You can have two choices for this to actually implement:
-
Using IIF, which got introduced from SQL Server 2012:
SELECT IIF ( (Obsolete = 'N' OR InStock = 'Y'), 1, 0) AS Saleable, * FROM Product -
Using
Select Case:SELECT CASE WHEN Obsolete = 'N' or InStock = 'Y' THEN 1 ELSE 0 END as Saleable, * FROM Product
Solution 22 - Sql
For those who uses SQL Server 2012, IIF is a feature that has been added and works as an alternative to Case statements.
SELECT IIF(Obsolete = 'N' OR InStock = 'Y', 1, 0) AS Salable, *
FROM Product
Solution 23 - Sql
SELECT
if((obsolete = 'N' OR instock = 'Y'), 1, 0) AS saleable, *
FROM
product;
Solution 24 - Sql
SELECT IIF(Obsolete = 'N' OR InStock = 'Y',1,0) AS Saleable, * FROM Product
Solution 25 - Sql
Question:
SELECT IF(Obsolete = 'N' OR InStock = 'Y' ? 1 : 0) AS Saleable, * FROM Product
ANSI:
Select
case when p.Obsolete = 'N'
or p.InStock = 'Y' then 1 else 0 end as Saleable,
p.*
FROM
Product p;
Using aliases -- p in this case -- will help prevent issues.
Solution 26 - Sql
Using SQL CASE is just like normal If / Else statements. In below query, If obsolete value = 'N' or If InStock value = 'Y' Then Output will be 1. Otherwise output will be 0. Then we put that 0 or 1 value under the Salable Column.
SELECT
CASE
WHEN obsolete = 'N' OR InStock = 'Y'
THEN 1
ELSE 0
END AS Salable
, *
FROM PRODUCT
Solution 27 - Sql
It will be something like that:
SELECT OrderID, Quantity,
CASE
WHEN Quantity > 30 THEN "The quantity is greater than 30"
WHEN Quantity = 30 THEN "The quantity is 30"
ELSE "The quantity is under 30"
END AS QuantityText
FROM OrderDetails;
Solution 28 - Sql
I like the use of the CASE statements but the question asked for an IF statement in the SQL Select. What I've used in the past has been:
SELECT
if(GENDER = "M","Male","Female") as Gender
FROM ...
It's like the excel or sheets IF statements where there is a conditional followed by the true condition and then the false condition:
if(condition, true, false)
Furthermore, you can nest the if statements (but then use should use a CASE :-)
(Note: this works in MySQLWorkbench but may not work in other platforms)
Solution 29 - Sql
SELECT
CAST(
CASE WHEN Obsolete = 'N'
or InStock = 'Y' THEN ELSE 0 END AS bit
) as Saleable, *
FROM
Product
Solution 30 - Sql
For the sake of completeness, I would add that SQL uses three-valued logic. The expression:
obsolete = 'N' OR instock = 'Y'
Could produce three distinct results:
| obsolete | instock | saleable |
|----------|---------|----------|
| Y | Y | true |
| Y | N | false |
| Y | null | null |
| N | Y | true |
| N | N | true |
| N | null | true |
| null | Y | true |
| null | N | null |
| null | null | null |
So for example if a product is obsolete but you dont know if product is instock then you dont know if product is saleable. You can write this three-valued logic as follows:
SELECT CASE
WHEN obsolete = 'N' OR instock = 'Y' THEN 'true'
WHEN NOT (obsolete = 'N' OR instock = 'Y') THEN 'false'
ELSE NULL
END AS saleable
Once you figure out how it works, you can convert three results to two results by deciding the behavior of null. E.g. this would treat null as not saleable:
SELECT CASE
WHEN obsolete = 'N' OR instock = 'Y' THEN 'true'
ELSE 'false' -- either false or null
END AS saleable
Solution 31 - Sql
You can use Case Statement:
Select
Case WHEN (Obsolete = 'N' or InStock = 'Y') THEN 1 ELSE 0 END Saleable,
Product.*
from Product
Solution 32 - Sql
There are multiple conditions.
SELECT
(CASE
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1001' THEN 'DM'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1002' THEN 'GS'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1003' THEN 'MB'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1004' THEN 'MP'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1005' THEN 'PL'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1008' THEN 'DM-27'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1011' THEN 'PB'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1012' THEN 'UT-2'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1013' THEN 'JGC'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1014' THEN 'SB'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1015' THEN 'IR'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1016' THEN 'UT-3'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1017' THEN 'UT-4'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1019' THEN 'KR'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1020' THEN 'SYB-SB'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1021' THEN 'GR'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1022' THEN 'SYB-KP'
WHEN RIGHT((LEFT(POSID,5)),4) LIKE '1026' THEN 'BNS'
ELSE ''
END) AS OUTLET
FROM matrixcrm.Transact
Solution 33 - Sql
You can find some nice examples in https://spikeslot.com/guides-and-tricks/ca, and I think the statement that you can use will be something like this (from spikeslot.com/ca):
SELECT
FirstName, LastName,
Salary, DOB,
CASE Gender
WHEN 'M' THEN 'Male'
WHEN 'F' THEN 'Female'
END
FROM Employees