Tag Archives: Functions

How to troubleshoot error – Msg 195, Level 15, State 10, Line 1 ‘TRY_CONVERT’ is not a recognized built-in function name

While running the following code on a database on my SQL Server 2012 instance I got the following error message

USE BB
go
SELECT TRY_CONVERT(xml, 'MyClub')

TCerr1The reason for this error is that this function TRY_CONVERT is 110 compatible. Which means it will only run on a database with 110 compatibility. Upon checking the compatibility level, I found the database to be on 90 or SQL Server 2005 compatible.
TCerr2Resolution:
I had to change the compatibility level to 110 and then ran the code with success.

TCerr3

TRY_CONVERT function in SQL Server 2012

TRY_CONVERT is one of the new conversion function introduced in SQL SERVER 2012. It returns a value converted to the specified data type if the conversion succeeds. Otherwise,it returns returns NULL value when it fails to convert to a requested data type. TRY_CONVERT function raises an exception if we try to an convert expression to a type which is not explicitly permitted

The syntax for TRY_CONVERT is as follows

TRY_CONVERT ( data_type [ ( length ) ], expression [, style ] )

Let us now implement this function and see how it works with different examples

SELECT TRY_CONVERT(xml, 'Manchester United')
SELECT TRY_CONVERT(DATETIME, '02/18/2014 05:30',111)
SELECT TRY_CONVERT(INT, '40')

The output of the above as follows
TryCon1

Now let us see examples where this function might fail or throw an exception

SELECT TRY_CONVERT(xml, 40)

And the output is
TryCon2

SELECT TRY_CONVERT(DATETIME, '22/18/2014 05:30',111)

And the output is
TryCon3The first error is self explanatory. The second code gives an output of NULL because the date is an invalid date.

Now the question is how is TRY_CONVERT different from CONVERT function?

Lets understand with this example

SELECT CONVERT(DATETIME, 'ABC')

TryCon4CONVERT will give an error message stating the conversion failed.

SELECT TRY_CONVERT(DATETIME, 'ABC')
AS 'Result'

TryCon5TRY_CONVERT will give a NULL.

 

PERCENT_RANK function in SQL Server 2012

PERCENT_RANK is a new function introduced in SQL Server 2012. The function calculates the relative rank of a row within a subset of rows or in simpler terms  it shows the percentage of values that are less than or equal to the current value.

The syntax for the function is as follows

 PERCENT_RANK( )
 OVER ( [ partition_by_clause ] order_by_clause )

Let us quickly implement PERCENT_RANK and understand how it works.

Use the following code to create a database with values in it.

USE [Master]
GO
IF EXISTS(SELECT name FROM sys.databases
WHERE name = 'PERCENTRANK')
BEGIN
DROP DATABASE PERCENTRANK;
END
GO
CREATE DATABASE PERCENTRANK;
GO
USE PERCENTRANK
GO
CREATE TABLE PERCENTRANKDEMO
(
[ProductId] int,
[SalesQty] int,
[Year] int
);
insert into PERCENTRANKDEMO
VALUES
(10,1000,2005),(20,1215,2005),(30,3327,2005),
(10,2000,2006),(20,2415,2006),(30,3429,2006),
(10,3050,2007),(20,3216,2007),(30,3737,2007),
(10,3026,2008),(20,1618,2008),(30,3452,2008),
(10,2004,2009),(20,4315,2009),(30,5435,2009),
(10,3040,2010),(20,4015,2010),(30,4343,2010),
(10,3060,2011),(20,4345,2011),(30,3237,2011),
(10,3075,2012),(20,4035,2012),(30,7450,2012),
(10,3055,2013),(20,5012,2013),(30,3321,2013),
(10,3059,2014),(20,6019,2014),(30,3245,2014),
(10,3150,2015),(20,6815,2015),(30,4000,2015);

Now lets use the PERCENT_RANK function on the above database created and view the outcome. We will use the following code below.

SELECT ProductId,SalesQty,Year,
PERCENT_RANK() OVER ( ORDER BY [SalesQty] )
AS PercentRank
FROM PERCENTRANKDEMO
WHERE productid = 30;

The outcome would be as below. The column PercentRank shows the percent of values that are less or equal to the current value of the SalesQty column. The first row in any set has a PERCENT_RANK of 0. That’s how it has been designed by default. In the result set 0.1 denotes 10 percent while 1 denotes 100 percent.
PR1

FIRST_VALUE – New analytical function in SQL Server 2012

In this article we will be taking a look at the new analytical function FIRST_VALUE  in SQL Server 2012. Let us understand them with examples.

This function returns the first value from an ordered set of values. The syntax for the same is

FIRST_VALUE ( [scalar_expression ] )
OVER ( [ partition_by_clause ]
order_by_clause [ rows_range_clause ] )

Let us create a sample table and understand this on SQL Server 2012. The following script does the same. Lets observe the output of the script below

CREATE TABLE [dbo].[MyFirstLastVaL](
[id] [int] IDENTITY(1,1) NOT NULL,
[Name] [nchar](10) NOT NULL,
[MarksInMaths] [int] NOT NULL )
GO
insert into MyFirstLastVaL values('Alan',99)
insert into MyFirstLastVaL values('Brent',29)
insert into MyFirstLastVaL values('Charlie',25)
insert into MyFirstLastVaL values('David',37)
insert into MyFirstLastVaL values('Ello',15)
insert into MyFirstLastVaL values('Frank',59)
insert into MyFirstLastVaL values('Grant',16)
insert into MyFirstLastVaL values('Honey',18)
insert into MyFirstLastVaL values('Irene',86)
insert into MyFirstLastVaL values('Jack',76)
insert into MyFirstLastVaL values('Kalou',66)
insert into MyFirstLastVaL values('Lisa',68)
insert into MyFirstLastVaL values('Mike',98)
insert into MyFirstLastVaL values('Lisa',28)
insert into MyFirstLastVaL values('Mike',45)
insert into MyFirstLastVaL values('Alan',19)
insert into MyFirstLastVaL values('Brent',92)
insert into MyFirstLastVaL values('Charlie',35)
insert into MyFirstLastVaL values('Irene',36)
insert into MyFirstLastVaL values('Jack',67)
insert into MyFirstLastVaL values('Kalou',96)

SELECT id,name,MarksInMaths,
FIRST_VALUE(marksinmaths) OVER (ORDER BY marksinmaths) MyFirstVal
FROM MyFirstLastVaL

fvl1Now let us use the function with partition by clause and observe the output

SELECT id,name,MarksInMaths,FIRST_VALUE(MarksInMaths)
OVER (PARTITION BY Name ORDER BY MarksInMaths) MyFirstVal
FROM MyFirstLastVaL

fvl2In the first case the query simply returns the first value of the entire data set whereas in the second case the output is based on the marksinmaths column, so the FIRST_VALUE is different but the same for each partition.

EOMONTH() – End of the month – SQL Server 2012

So how do we calculate the last date of the month which is 4 months from now?

SQL Server 2012 presents EOMONTH() function. Let us understand this function with an example.

DECLARE @MyDate datetime
SET @MyDate = GETDATE()
SELECT EOMONTH (@MyDate,4)
SELECT EOMONTH (@MyDate,-4)
as LastDayOfTheMonth

eom2
So what do we find from the 2 outputs. Well it gives me the last date of the 4th month from the current month i.e. 4 months from now would be April and the last date of April is 30th. The second output gives the last date of 4 months previous i.e August. This function would be very handy in calculations where the last date of the month is a critical factor. Previously to achieve this we would have to do a bit of manipulation.

TRY_PARSE – Conversion function in SQL Server 2012

In this article I will discuss about the TRY_PARSE function in SQL Server 2012. Conversion functions helps us avoid errors when dealing with different data types. Let us understand TRY_PARSE with an example.

SELECT TRY_PARSE ('12-18-2013' AS datetime) AS Alpha
SELECT TRY_PARSE ('2013' AS decimal) AS Beta
SELECT TRY_PARSE ('2013.00' AS decimal) AS Gamma
SELECT TRY_PARSE ('2013.0000' AS float) AS Theta
SELECT TRY_PARSE ('Arsenal' AS float) AS Delta

The TRY_PARSE() function can convert any string value to a Numeric or Date/Time format. If the passed string value cannot be converted to Numeric or Date/Time format, it will result to a NULL.

Lets have a look at the output of the above
TP2In the above case it would not convert ‘Arsenal’ to a date time or Numeric value and hence it results in NULL output. TRY_PARSE function is not a native SQL SERVER function, instead it is a CLR dependent function.

Format() function in SQL Server 2012

SQL Server 2012 introduces this new function called FORMAT which returns a value in the specified format and also can optionally apply a regional format. This function relies on the .NET Framework.

In this article we will explore this function and see how it can be implemented.

FORMAT() accepts 3 parameters. The first parameter is the VALUE parameter where we pass on the date value or a numeric value. The second parameter is the .NET Framework format string. The format parameter is case sensitive. The third parameter is the culture. This can be any culture supported by the .NET Framework.

Let us now explore this function with some examples:
1) Display the date using Bengali Culture

DECLARE @date DATETIME = '12/04/2013';
SELECT FORMAT ( @date, 'MMMM dddd dd yyyy', 'Bn-IN' )
 AS DateInBangla;

format12) Display the date using Tamil Culture

DECLARE @date DATETIME = '12/04/2013';
SELECT FORMAT ( @date, 'MMMM dddd dd yyyy', 'Ta-IN' ) AS
DateInTamil;

format23) Display an amount into different currency structures

SELECT FORMAT(100, 'C', 'en-GB') AS Pounds,
FORMAT(100, 'C', 'en-US') AS Dollars,
FORMAT(100, 'C', 'es-ES') AS Euro,
FORMAT(100, 'C', 'en-IN') AS Rs;
GO

format34) Display current date time in US format

SELECT FORMAT(GETDATE(), N'"Time now is "dddd MMMM dd, yyyy', 'en-US')
AS USTimeStamp;

format4For more details on this function please refer to this msdn link.

%d bloggers like this: