How do you write a case statement in SQL Select query?

Can we use select query in 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. … Once a condition is satisfied, its corresponding value is returned.

How do I add a case statement to a select clause?

The CASE statement always goes in the SELECT clause. CASE must include the following components: WHEN , THEN , and END . ELSE is an optional component. You can make any conditional statement using any conditional operator (like WHERE ) between WHEN and THEN .

How does case work in SQL?


  1. CASE WHEN is used to determine conditional statements in SQL. CASE declares the start of the conditions. WHEN declares a condition. THEN declares the return of a true condition. …
  2. You can have a multitude of WHEN statements.
  3. AS can be used to create a header for the return data, otherwise it is given the header “case”
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How do you write a switch case in SQL query?

SQL CASE Statement

  1. CASE. WHEN condition1 THEN result1. WHEN condition2 THEN result2. WHEN conditionN THEN resultN. ELSE result. …
  2. Example. SELECT OrderID, Quantity, CASE. WHEN Quantity > 30 THEN ‘The quantity is greater than 30’ …
  3. Example. SELECT CustomerName, City, Country. FROM Customers. (CASE.

Can we write select inside case?

The CASE expression is a conditional expression: it evaluates data and returns a result. The result it returns is based on whether the data meets certain criteria. This expression can be used in SELECT , UPDATE , and DELETE statements or in WHERE , IN , LIKE , ORDER BY , and HAVING clauses.

Can I use select inside case?

The Case statement in SQL is mostly used in a case with equality expressions. The SQL Case statement is usually inside of a Select list to alter the output. What it does is evaluates a list of conditions and returns one of the multiple possible result expressions.

Can we write CASE statement in where clause?


We can use a case statement in Where, Order by and Group by clause. … So, by using a CASE statement with the where condition displays the result.

Can you use CASE statement in where clause?

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.

Can we use CASE statement in update query?

I have SQL server Table in which there is column that I wanted to update according to a 2 columns value that are present in current row. In this scenario, we can use CASE expression. CASE statement works like IF-THEN-ELSE statement. …

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How many tables can be join in SQL query?

Theoretically, there is no upper limit on the number of tables that can be joined using a SELECT statement. (One join condition always combines two tables!) However, the Database Engine has an implementation restriction: the maximum number of tables that can be joined in a SELECT statement is 64.

How do you do not in SQL?

Overview. The SQL Server NOT IN operator is used to replace a group of arguments using the <> (or !=) operator that are combined with an AND. It can make code easier to read and understand for SELECT, UPDATE or DELETE SQL commands.

What is switch in SQL?

The function SWITCH evaluate a list of expressions and returns the value of the first expression that TRUE is. If there are no expression TRUE then it returns NULL. This is not a standard function and exist for compatible with MS Access. SQL Syntax: SWITCH( expression1, value1, expression2, value2, …)

Can we use if statement in select query in SQL?

Else statement in SQL Server. If the condition evaluates to True, then T-SQL statements followed by IF condition in SQL server will be executed. … If the condition evaluates to False, then T-SQL statements followed by ELSE keyword will be executed.

What is a case expression?

A CASE expression returns a value. CASE expression has two formats: … This format compares a value expression to a set of value expressions to determine a result. The value expressions are evaluated in their order listed. If a value expression evaluates to TRUE, CASE returns the value expression for the THEN clause.

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