CODEWITHSUNDEEP
t-sqlsql-server
Malfist
Malfist

Reputation: 31795

Getting the minimum of two values in SQL

I have two variables, one is called PaidThisMonth, and the other is called OwedPast. They are both results of some subqueries in SQL. How can I select the smaller of the two and return it as a value titled PaidForPast?

The MIN function works on columns, not variables.

Upvotes: 250

Views: 428229

Answers (12)

Gil Margolin
Gil Margolin

Reputation: 2119

For SQL Server 2022+ (or MySQL or PostgreSQL 9.3+), a better way is to use the LEAST and GREATEST functions.

SELECT GREATEST(A.date0, B.date0) AS date0, 
       LEAST(A.date1, B.date1, B.date2) AS date1
FROM A, B
WHERE B.x = A.x

With:

  • GREATEST(value [, ...]) : Returns the largest (maximum-valued) argument from values provided
  • LEAST(value [, ...]) Returns the smallest (minimum-valued) argument from values provided

Documentation links :

Upvotes: 66

Сергей Седых
Сергей Седых

Reputation: 155

SELECT (WHEN first > second THEN second ELSE first END) the_minimal FROM table

Upvotes: -1

Lawrence
Lawrence

Reputation: 29

This works for up to 5 dates and handles nulls. Just couldn't get it to work as an Inline function.

CREATE FUNCTION dbo.MinDate(@Date1 datetime = Null,
                            @Date2 datetime = Null,
                            @Date3 datetime = Null,
                            @Date4 datetime = Null,
                            @Date5 datetime = Null)
RETURNS Datetime AS
BEGIN
--USAGE select dbo.MinDate('20120405',null,null,'20110305',null)
DECLARE @Output datetime;

WITH Datelist_CTE(DT)
AS (
        SELECT @Date1 AS DT WHERE @Date1 is not NULL UNION
        SELECT @Date2 AS DT WHERE @Date2 is not NULL UNION
        SELECT @Date3 AS DT WHERE @Date3 is not NULL UNION
        SELECT @Date4 AS DT WHERE @Date4 is not NULL UNION
        SELECT @Date5 AS DT WHERE @Date5 is not NULL
   )
Select @Output=Min(DT) FROM Datelist_CTE;

RETURN @Output;
END;

Upvotes: 2

DaveX
DaveX

Reputation: 745

Building on the brilliant logic / code from mathematix and scottyc, I submit:

DECLARE @a INT, @b INT, @c INT = 0;

WHILE @c < 100
    BEGIN
        SET @c += 1;
        SET @a = ROUND(RAND()*100,0)-50;
        SET @b = ROUND(RAND()*100,0)-50;
        SELECT @a AS a, @b AS b,
            @a - ( ABS(@a-@b) + (@a-@b) ) / 2 AS MINab,
            @a + ( ABS(@b-@a) + (@b-@a) ) / 2 AS MAXab,
            CASE WHEN (@a <= @b AND @a = @a - ( ABS(@a-@b) + (@a-@b) ) / 2)
            OR (@a >= @b AND @a = @a + ( ABS(@b-@a) + (@b-@a) ) / 2)
            THEN 'Success' ELSE 'Failure' END AS Status;
    END;

Although the jump from scottyc's MIN function to the MAX function should have been obvious to me, it wasn't, so I've solved for it and included it here: SELECT @a + ( ABS(@b-@a) + (@b-@a) ) / 2. The randomly generated numbers, while not proof, should at least convince skeptics that both formulae are correct.

Upvotes: 2

Sergej Loos
Sergej Loos

Reputation: 312

Select MIN(T.V) FROM (Select 1 as V UNION Select 2 as V) T

Upvotes: 1

Mert G&#252;lsoy
Mert G&#252;lsoy

Reputation: 2919

SQL Server 2012 and 2014 supports IIF(cont,true,false) function. Thus for minimal selection you can use it like

SELECT IIF(first>second, second, first) the_minimal FROM table

While IIF is just a shorthand for writing CASE...WHEN...ELSE, it's easier to write.

Upvotes: 224

Charles Bretana
Charles Bretana

Reputation: 146469

Use Case:

   Select Case When @PaidThisMonth < @OwedPast 
               Then @PaidThisMonth Else @OwedPast End PaidForPast

As Inline table valued UDF

CREATE FUNCTION Minimum
(@Param1 Integer, @Param2 Integer)
Returns Table As
Return(Select Case When @Param1 < @Param2 
                   Then @Param1 Else @Param2 End MinValue)

Usage:

Select MinValue as PaidforPast 
From dbo.Minimum(@PaidThisMonth, @OwedPast)

ADDENDUM: This is probably best for when addressing only two possible values, if there are more than two, consider Craig's answer using Values clause.

Upvotes: 148

Mike Cole
Mike Cole

Reputation: 14703

Use a CASE statement.

Example B in this page should be close to what you're trying to do:
http://msdn.microsoft.com/en-us/library/ms181765.aspx

Here's the code from the page:

USE AdventureWorks;
GO
SELECT   ProductNumber, Name, 'Price Range' = 
      CASE 
         WHEN ListPrice =  0 THEN 'Mfg item - not for resale'
         WHEN ListPrice < 50 THEN 'Under $50'
         WHEN ListPrice >= 50 and ListPrice < 250 THEN 'Under $250'
         WHEN ListPrice >= 250 and ListPrice < 1000 THEN 'Under $1000'
         ELSE 'Over $1000'
      END
FROM Production.Product
ORDER BY ProductNumber ;
GO

Upvotes: 6

mathematix
mathematix

Reputation: 366

Here is a trick if you want to calculate maximum(field, 0):

SELECT (ABS(field) + field)/2 FROM Table

returns 0 if field is negative, else, return field.

Upvotes: 16

Craig
Craig

Reputation: 4682

The solutions using CASE, IIF, and UDF are adequate, but impractical when extending the problem to the general case using more than 2 comparison values. The generalized solution in SQL Server 2008+ utilizes a strange application of the VALUES clause:

SELECT
PaidForPast=(SELECT MIN(x) FROM (VALUES (PaidThisMonth),(OwedPast)) AS value(x))

Credit due to this website: http://sqlblog.com/blogs/jamie_thomson/archive/2012/01/20/use-values-clause-to-get-the-maximum-value-from-some-columns-sql-server-t-sql.aspx

Upvotes: 177

user1970604
user1970604

Reputation: 19

Use a temp table to insert the range of values, then select the min/max of the temp table from within a stored procedure or UDF. This is a basic construct, so feel free to revise as needed.

For example: 

CREATE PROCEDURE GetMinSpeed() AS
BEGIN

    CREATE TABLE #speed (Driver NVARCHAR(10), SPEED INT);
    '
    ' Insert any number of data you need to sort and pull from
    '
    INSERT INTO #speed (N'Petty', 165)
    INSERT INTO #speed (N'Earnhardt', 172)
    INSERT INTO #speed (N'Patrick', 174)

    SELECT MIN(SPEED) FROM #speed

    DROP TABLE #speed

END

Upvotes: 1

MartinC
MartinC

Reputation: 885

I just had a situation where I had to find the max of 4 complex selects within an update. With this approach you can have as many as you like!

You can also replace the numbers with aditional selects

select max(x)
 from (
 select 1 as 'x' union
 select 4 as 'x' union
 select 3 as 'x' union
 select 2 as 'x' 
 ) a

More complex usage

 @answer = select Max(x)
           from (
                select @NumberA as 'x' union
                select @NumberB as 'x' union
                select @NumberC as 'x' union
                select (
                       Select Max(score) from TopScores
                       ) as 'x' 
     ) a

I'm sure a UDF has better performance.

Upvotes: 39

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