Sql case statement

Transform SQL Data into Stunning Reports. Get Your Free Trial Today. Watch the Free Tableau Video Demo! Move Forward With Confidence. Connecting With The Data Community.

CASE can be used in any statement or clause that allows a valid expression. For example, you can use CASE in statements such as SELECT, UPDATE, DELETE and SET, and in clauses such as select_list , IN, WHERE, ORDER BY, and HAVING. So, once a condition is true, it will stop reading and return the result. If no conditions are true, it will return the value in the ELSE clause.

In SQL Server ( Transact-SQL ), the CASE statement has the functionality of an IF-THEN-ELSE statement. If there is no ELSE part and no conditions are true, it returns NULL. You can use the CASE statement within a SQL statement.

Because of this pairing, you might be tempted to call this SQL CASE WHEN, but CASE is the accepted term. According to Ms SQL Docs a CASE statement can be used throughout the SELECT statement. The CASE expression has two formats: simple CASE and searched CASE. This statement resembles Visual Basics Select Case statement.

The following example uses the CASE expression to change the display of product line categories to make them more understandable. The SQL CASE statement has WHEN, THEN, and ELSE clauses along with an END terminator. OR is not supported with CASE Statement in SQL. How does case statement work in SQL?

The CASE statement chooses from a sequence of conditions, and executes a corresponding statement. How to create a SQL statement? What is statement syntax in SQL? The simple SQL CASE statement is used for equality tests. It tests one expression against multiple values, this makes it great for transforming one set of values, such as abbreviations to their corresponding long form.

The searched SQL CASE statement uses a more comprehensive expression evaluation format. ELSE block in CASE statement holds the sequence that needs to be executed when none of the alternatives got selected. A selector can be anything such as variable, function, or expression that the CASE statement evaluates to a Boolean value. Note that this behavior of the CASE statement is different from the IF THEN statement.

It’s good for displaying a value in the SELECT query based on logic that you have defined. As the data for columns can vary from row to row, using a CASE SQL expression can help make your data more readable and useful to the user or to the application. In this tutorial, we have introduced you to the SQL CASE statement that allows you to add the IF THEN ELSE logic to the SQL.

Pinal Dave is a SQL Server Performance Tuning Expert and an independent consultant. Your first problem is that there is no CASE statement in SQL. This is a declarative language and we have a CASE expression.

Expressions return scalar values. The CASE works by first finding the data type of the THEN and ELSE clause to use for the result. The SQL Case Statement is similar to the control flow statements (something like IF ELSE). This Sql Server Case statement evaluates the series of conditional expressions provided in CASE WHEN, and returns the result set. There are two type of SQL Server Case Statements , and they are: Boolean.

However, to select the sequence, the CASE statement uses a selector rather than multiple Boolean expressions. A selector is an expression, the value of which is used to select one of several alternatives. CASE is used to provide if-then-else type of logic to SQL. The second is a Searched CASE expression, where we compare an expression to one or more logical conditions. Unlike IF…ELSE, where only the maximum of one condition is allowe CASE allows the user to apply multiple conditions to perform different sets of actions in MS SQL.

In MS SQL, there are two types of CASE. My SQL CASE Statement Summary : in this tutorial, you will learn how to use MySQL CASE statements to construct complex conditional statements inside stored procedures. Besides the IF statement, MySQL provides an alternative conditional statement called the CASE statement for constructing conditional statements in stored procedures. This form is useful within a SELECT or UPDATE statement if a table contains a limited number of values in a column and you want to associate a corresponding result value to each of those column values. SQL Server CASE Statement and CASE WHEN Examples 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.