Select case sql

SQL Server allows for only levels of nesting in CASE expressions. For a list of control-of-flow methods, see Control-of-Flow Language ( Transact-SQL ). So, once a condition is true, it will stop reading and return the result. We can use a Case statement in select queries along with Where, Order By and Group By clause. It can be used in Insert statement as well.

In this article, we would explore CASE statement and its various use cases. If you wanted to assign that to a variable you would put it before the CASE statement). What is a SELECT statement in SQL?

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. How to use case in SQL? In MS SQL , there are two types of CASE. This statement resembles Visual Basics Select Case statement. Because of this pairing, you might be tempted to call this SQL CASE WHEN, but CASE is the accepted term.

The SQL CASE statement has WHEN, THEN, and ELSE clauses along with an END terminator. Definition and Usage. The CASE statement goes through conditions and return a value when the first condition is met (like an IF-THEN-ELSE statement).

If no conditions are true, it will return the value in the ELSE clause. If there is no ELSE part and no conditions are true, it returns. The Select Case statement is used to control the flow of statements depending on the value of the control expression (variable) and the comparative conditions specified by the Case keyword. The script for Select Case in MS Access is: You can have an unlimited amount of Cases, more than two, as in our example.

It starts with the CASE keyword followed by the WHEN keyword and then the CONDITION. You can use a more compact form of the SQL CASE expression if you’re comparing a test value for equality with a series of other values. CASE is used to provide if-then-else type of logic to SQL.

There are two formats: The first is a Simple CASE expression, where we compare an expression to static values. The second is a Searched CASE expression, where we compare an expression to one or more logical conditions. Both of CASE expression formats support an optional ELSE statement.

The CASE expression has two formats: simple CASE expression and searched CASE expression. Because CASE is an expression, you can use it in any clause that accepts an expression such as SELECT , WHERE, GROUP BY, and HAVING. Hi SELECT with a CASE statement will not work in 8i when using static SQL. However if you are using dynamic SQL to execute it, then it will be fine. According to Ms SQL Docs, a CASE statement can be used throughout the SELECT statement.

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. The SEARCHED CASE statement is similar to the CASE statement, rather than using the selector to select the alternative, SEARCHED CASE will directly have the expression defined in the WHEN clause. The first WHEN clause that satisfies the condition will be execute and the controller will skip the remaining alternatives.

Oracle Database uses short-circuit evaluation.