What is SQL CASE statement?

What is SQL CASE statement?

The case statement in SQL returns a value on a specified condition. We can use a Case statement in select queries along with Where, Order By, and Group By clause. It can be used in the Insert statement as well. In Case statement, we defined conditions. Once a condition is satisfied, its corresponding value is returned.

How do I use multiple case statements in SQL?

SELECT (case A. column1 when ‘1’ then (select value from B where B. clientId=100 and ‘1’=B.Id) when ‘2’ then (select value from C where C.

What are the types of the CASE statement?

The CASE statement has two types: simple CASE statement and searched CASE statement. Both types of the CASE statements support an optional ELSE clause.

How do I count cases in SQL?

SQL CASE Use CASE to COUNT the number of rows in a column match a condition.

1. Use Case.
2. Query SELECT COUNT(Id) AS ItemsCount, SUM ( CASE WHEN PriceRating = ‘Expensive’ THEN 1 ELSE 0 END ) AS ExpensiveItemsCount FROM ItemSales.
3. Results:

How do you end a case statement?

The CASE statement ends with an END keyword.

What makes a good case statement?

It should be simple, clear, and persuasive. The case statement, however, should not just be reserved for big fundraisers such as a capital campaign. It should serve as the basis for all of your efforts to persuade people to support your mission, whether that is a social media campaign or a pitch to a major donor.

How do you use multiple values in a case statement?

SQL:2003 standard allows to define multiple values for simple case expression: SELECT CASE c. Number WHEN ‘1121231’,’31242323′ THEN 1 WHEN ‘234523’,’2342423′ THEN 2 END AS Test FROM tblClient c; It is optional feature: Comma-separated predicates in simple CASE expression“ (F263).

Can we write case inside case in SQL?

Nested CASE: CASE in IF ELSE In the above example CASE is NESTED inside IF…ELSE statement: First, IF Statement will execute and if Case Condition in SQL server is False then ELSE statement will execute. Else contain Nested CASE Statement in SQL inside it.

What is the main use of a CASE statement?

The CASE statement is used to retrieve data based on a few conditions. So, once the condition is met, then it will stop reading the data and return the required results. In a scenario, where no conditions are met, then it returns the values from the ELSE clause.

How must you end a CASE statement?

The WHEN clause for which the expression returns TRUE will be executed. ‘ELSE’ block is optional which hold the that needs to be executed when none of the alternatives satisfies. The ‘END’ marks the end of the CASE statement and, it is a mandatory part of CASE.

How does a simple CASE statement in SQL work?

A simple CASE statement expression In this format, we evaluate one expression against multiple values. In a simple case statement, it evaluates conditions one by one. Once the condition and expression are matched, it returns the expression mentioned in THEN clause.

Can you have more than 10 case statements in SQL Server?

I need to breakdown some information with just initials (sometimes 2, sometimes 3 if the initials are already used) SQL Server throws the error of: Case expressions may only be nested to level 10.

Can you have more than one condition in a case statement?

We can have multiple conditions in a Case statement; however, it works in a sequential model. If one condition is satisfied, it stops checking further conditions The Case statement in SQL provides flexibility in writing t-SQL for DDL and DML queries. It also adds versatility to SQL Server queries.

When do you use the case keyword in SQL?

Case keyword is followed by the WHEN statement, and there is no expression between CASE and WHEN. E.g.: CASE WHEN <Boolean_Expression_1> THEN Statement_1…. In Simple Case, VALUE exists for each WHEN statement.