Category: SQL Server

If you’ve been following this blog, you’ll know that I write a fair bit of SQL. I’m going to post some small snippets of SQL which I had to work out how to accomplish a small task as part of a larger script.

In thi spost, I am going to show how use ROW_NUMBER to generate a unique row number. There are three examples of code.

This first example, the simplest of the three, shows how to generate a unique number for each row in the recordset:

/*
Created by Ian Grieve of azurecurve|Ramblings of a Dynamics GP Consultant (https://www.azurecurve.co.uk)
This code is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.0 UK: England & Wales (CC BY-NC-SA 2.0 UK).
*/
SELECT
	PONUMBER
	,ORD
	,ITEMNMBR
	,ITEMDESC
	,ROW_NUMBER() OVER(ORDER BY PONUMBER, ORD ASC) AS CUSTOM_ROW_ID
FROM
	POP30110
GO

The second example, shows a row number can be assigned to the lines of each transaction (this is accomplished :

/*
Created by Ian Grieve of azurecurve|Ramblings of a Dynamics GP Consultant (https://www.azurecurve.co.uk)
This code is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.0 UK: England & Wales (CC BY-NC-SA 2.0 UK).
*/
SELECT
	PONUMBER
	,ORD
	,ITEMNMBR
	,ITEMDESC
	,ROW_NUMBER() OVER(PARTITION BY PONUMBER ORDER BY PONUMBER, ORD ASC) AS CUSTOM_ROW_ID
FROM
	POP30110
GO

This final example, takes the first example and shows how we can select a range of row numbers (this is useful if you are selecting data to display on a page):

/*
Created by Ian Grieve of azurecurve|Ramblings of a Dynamics GP Consultant (https://www.azurecurve.co.uk)
This code is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.0 UK: England & Wales (CC BY-NC-SA 2.0 UK).
*/
WITH POTRX AS
	(SELECT
		PONUMBER
		,ORD
		,ITEMNMBR
		,ITEMDESC
		,ROW_NUMBER() OVER(ORDER BY PONUMBER ORDER BY PONUMBER, ORD ASC) AS CUSTOM_ROW_ID
	FROM
		POP30110)
SELECT
	*
FROM
	POTRX
WHERE
	CUSTOM_ROW_ID BETWEEN 40 AND 59
GO

If you’ve been following this blog, you’ll know that I write a fair bit of SQL. I’m going to post some small snippets of SQL which I had to work out how to accomplish a small task as part of a larger script.

This second example, shows how to format a date in two of the most common formats I work with. Each example returns the date using the FORMAT command introduced in SQL Server 2012 and the more traditional method.

The first example, returns the date as day month year separated with /:

/*
Created by Ian Grieve of azurecurve|Ramblings of a Dynamics GP Consultant (https://www.azurecurve.co.uk)
This code is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.0 UK: England & Wales (CC BY-NC-SA 2.0 UK).
*/
DECLARE @DATE DATETIME = '2017-05-31 11:59:59.000'

SELECT
	CONVERT(VARCHAR(10), @DATE, 103)
	,FORMAT(@DATE, 'dd/MM/yyyy')

The second returns the date in ISO 8601 format:

/*
Created by Ian Grieve of azurecurve|Ramblings of a Dynamics GP Consultant (https://www.azurecurve.co.uk)
This code is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.0 UK: England & Wales (CC BY-NC-SA 2.0 UK).
*/
DECLARE @DATE DATETIME = '2017-05-31 11:59:59.000'

SELECT
	CONVERT(VARCHAR(10), @DATE, 126)
	,FORMAT(@DATE, 'yyyy-MM-dd')

Last year I posted a script to find tables containing a particular column using sys objects. Steve Endow of Dynamics GP Land suggested using the INFORMATION_SCHEMA instead as he found it easier to use.

I’ve recently had reason to search for tables with a particular column in them, so I took a look at using a script using INFORMATION_SCHEMA.COLUMNS. However, when taking a detailed look at the results I found a few anomalies; the issue was that INFORMATION_SCHEMA.COLUMNS returns results for columns in not only tables, but also views. Which does make sense as both tables and views have columns. For what I was working on I needed a list of only tables.

I did a little exploring of the INFORMATION_SCHEMA and determined that I could join to INFORMATION_SCHEMA.TABLES and filter on TABLE_TYPE <> ‘VIEW’ to get a result set of only tables:

/*
Created by Ian Grieve of azurecurve|Ramblings of a Dynamics GP Consultant (https://www.azurecurve.co.uk)
This code is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0 Int).
*/
DECLARE @ColumnToFind VARCHAR(20) = 'PAYRCORD'
SELECT
	['Tables'].TABLE_SCHEMA AS 'Schema'
	,['Tables'].TABLE_NAME AS 'Table'
FROM
	INFORMATION_SCHEMA.COLUMNS AS ['Columms']
INNER JOIN
	INFORMATION_SCHEMA.TABLES AS ['Tables']
		ON
			['Tables'].TABLE_CATALOG = ['Columms'].TABLE_CATALOG
		AND
			['Tables'].TABLE_SCHEMA = ['Columms'].TABLE_SCHEMA
		AND
			['Tables'].TABLE_NAME = ['Columms'].TABLE_NAME
		AND
			['Tables'].TABLE_TYPE <> 'VIEW'
WHERE
	COLUMN_NAME = @ColumnToFind
ORDER BY
	'Schema'
	,'Table'

In the original posts script I was using the sys objects directly, but was filtering out the views by joining to sys.tables which contains only tables. Both the original script and the above one return exactly the same result set.

So, what’s the difference?

INFORMATION_SCHEMA, or System Information Schema Views to give the full name, is one of several methods SQL Server provides to get an internal, system table-independent view of the SQL Server metadata. Information schema views enable applications to work correctly although significant changes may have been made to the underlying system tables. The information schema views included in SQL Server originally complied with the ISO standard definition for the INFORMATION_SCHEMA, but appear to have diverged from the standard as new standards have been introduced.

The metadata returned by INFORMATION_SCHEMA, comes from the sys objects. So by using the former you are getting information from the latter, but in a way which should be future proofed against database changes.