SQL Server: CASE Statement - techonthenet.com.
Description. The Microsoft Excel CASE statement has the functionality of an IF-THEN-ELSE statement. The CASE statement is a built-in function in Excel that is categorized as a Logical Function.It can be used as a VBA function (VBA) in Excel.
The CASE expression has two formats: simple CASE and searched CASE. You can use the CASE expression in a clause or statement that allows a valid expression. For example, you can use the CASE expression in statements such as SELECT, DELETE, and UPDATE or in clauses such as SELECT, ORDER BY, and HAVING.
In SQL, you can use a CASE expression to change the contents of a table field from a definite value to a null value. The null value indicates that you no longer know the field’s value. Consider the following example. Imagine that you own a small airline that offers flights between Southern California and Washington state.
Many a times there’s a need to create a derived column in an output, based on some condition. The condition is similar to the typical if construct we use if many programming languages. In SQL scripting, we can use Case expressions or Case Statements as you may call them, to create a derived column based on a condition. Also read about Nested Case Statements in SQL Server.
Alias for case statement. 1.23.16. Use two case statements in one select statement. 1.23.17. Case then with query. 1.23.18. Case with range. 1.23.19. Doing a calculation in a Searched CASE.
SQL Using a Case Statement in a SQL Where Clause It is common knowledge that you can apply a Case statement in the SELECT or ORDER BY portion of a SQL statement. What isn’t well known is that you can use it effectively in a WHERE clause.
In the SQL query, an UPDATE statement writes longer to a table than a CASE statement, because of its logging. An inline CASE statement chooses what is preferred before writing it on the table, thus increasing the speeds. 5. Reduce nested views to reduce lags.