Articles tagged

28 February 2011
28 February 2011

The EXCEPT and INTERSECT Operators in SQL Server

The UNION, EXCEPT and INTERSECT operators of SQL enable you to combine more than one SELECT statement to form a single result set. The UNION operator returns all rows. The INTERSECT operator returns all rows that are in both result sets. The EXCEPT operator returns the rows that are only in the first result set but not in the second. Simple? Rob Sheldon explains all, with plenty of examples… Read more
06 January 2011
06 January 2011

Data Conversion in SQL Server

Most of the time, you do not have to worry about implicit conversion in SQL expressions, or when assigning a value to a column. Just occasionally, though, you'll find that data gets truncated, queries run slowly, or comparisons just seem plain wrong. Robert explains why you sometimes need to be very careful if you mix data types when manipulating values. … Read more
25 November 2010
25 November 2010

The DELETE statement in SQL Server

Of the big four DML statements in SQL Server, the DELETE is the one least written about. This is odd considering the extra power conferred on the statement by the addition of the WITH common_table_expression; and the OUTPUT clause that essentially allows you to move data from one table to another in one statement. … Read more
28 October 2010
28 October 2010

Working with Window Functions in SQL Server

With SQL Server 2005, SQL Server introduced some of SQL's window functions, that apply, not to the full set, but a partitioned 'window'. Although the ROW_NUMBER, RANK, NTILE and DENSE_RANK bring great power to TSQL, the full versatility will not be available until SQL Server delivers the full implementation. As usual, Robert Sheldon explains all. … Read more
27 September 2010
27 September 2010

Working with the INSERT statement in SQL Server

The INSERT statement in SQL Server is versatile. It now allows the insertion of multiple rows of literal values. It also provides the output clause that solves a number of common problems such as ascertaining the value of identity fields, and other calculated fields in tables, or for auditing the rows that are added to tables. Robert, once again, gives a clear introduction. … Read more
29 April 2010
29 April 2010

SQL Server CTE Basics

The CTE was introduced into standard SQL in order to simplify various classes of SQL Queries for which a derived table just wasn't suitable. For some reason, it can be difficult to grasp the techniques of using it. Well, that's before Rob Sheldon explained it all so clearly for us.… Read more