Today junior Application Developer asked me what are the causes of poor performance queries in SQL Server? This is a very open ended question and there could be a lot if reasons behind the poor performance of a query....
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Posts in the [ T-SQL ] Category
Dynamic date range based on todays date
I had the challenge of putting together a T-SQL statement that's going to be used in a few stored procedures. The stored procedures will build data based on what todays date is, if today is greater than second Tuesday of...
Read More70-461 Querying Microsoft SQL Server 2012
Introduction
70-461 Querying Microsoft SQL Server 2012 is an exam designed by Microsoft to test the skills and experience of SQL Server users. It's recommended that you have two years experience before sitting the exam, however, it's not a... Read MoreINTERSECT and EXCEPT
INTERSECT and EXCEPT are operators within SQL Server that takes data from two queries and compares the results.
INTERSECT returns the distinct values from both the left query and right query.
EXCEPT is different as it returns...
UNION and UNION ALL
UNION and UNION ALL are used for joining two or more datasets together. The datasets need to return the same number of columns. The columns names of all datasets can be different, however, the final results will have their columns...
Read MoreFORMAT
FORMAT is a function that is used return a NVARCHAR data type from a date/time or number. You can still use CAST or CONVERT for these and all other conversions. FORMAT is just another option that was introduced in SQL...
Read MoreANY, SOME and ALL
The SOME, ANY and ALL are logical operators that compare against a scalar value. This article is a simple overview of how they work.
Sample Data
[crayon-5c45f90a5b933593208153/]
SOME and ANY:
[crayon-5c45f90a5b93c917860485/] Results: [crayon-5c45f90a5b941146992387/] If the 50000 in the WHERE clause is... Read MoreSEQUENCE
Within SQL Server, SEQUENCE is a numeric order that has been defined by it's creator. The SEQUENCE can be generated in either an ascending or descending order, it can have intervals (gaps) within it's numbers and it can restart itself...
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