How Do I Add A Case Statement To A Select Clause?

Is null in Oracle?

Introduction to the Oracle IS NULL operator NULL is special in the sense that it is not a value like a number, character string, or datetime, therefore, you cannot compare it with any other values like zero (0) or an empty string (”).

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The IS NULL operator returns true if the expression or column is NULL ..

What can I use instead of case in SQL?

SELECT IIF ( -1 < 1, 'TRUE' , 'FALSE' ) AS Result; Let us see how both of the queries work and provides the results. You can see that in both of the above queries if we have to make a decision between two values, it would be easy to write IIF. However, there is something preventing users to use IIF.

How do you write multiple conditions in a case statement?

Case Statement in SQL Server (examples included)(1) For a single condition: CASE WHEN condition1 THEN result1 ELSE result2 END AS new_field_name.(2) For multiple conditions using AND: CASE WHEN condition1 AND condition2 THEN result1 ELSE result2 END AS new_field_name.More items…•

How do you write multiple cases in SQL?

You can use CASE with many WHEN like this;CASE WHEN Col1 = 1 OR Col3 = 1 THEN 1.WHEN Col1 = 2 THEN 2….ELSE 0 END as Qty.

How do I add a case statement in SQL?

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

How do you write a case statement?

The steps involved in writing your Case Statement: your mission statement and all other strategic materials (strategic plan, vision statement, etc.) your financial data (financial statements, fund usage, gaps, etc.) program analysis, reports, etc. (what worked and what didn’t work in the past)

How do I do an if statement in SQL?

Syntax. In the following SQL IF Statement, it evaluates the expression, and if the condition is true, then it executes the statement mentioned in IF block otherwise statements within ELSE clause is executed. We can understand SQL IF Statement using the following flow chart.

What is decode in Oracle?

DECODE compares expr to each search value one by one. If expr is equal to a search , then Oracle Database returns the corresponding result . If no match is found, then Oracle returns default . If default is omitted, then Oracle returns null.

Can we write select statement in case?

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 do I use NVL?

The Oracle NVL() function allows you to replace null with a more meaningful alternative in the results of a query. The NVL() function accepts two arguments. If e1 evaluates to null, then NVL() function returns e2 . If e1 evaluates to non-null, the NVL() function returns e1 .

How do you use max in a case statement?

Query 2 gets the MAX() of the values returned by the CASE expression. The CASE expression can return a value of “string1”, “string2”, or “string3”. Therefore if any row evaluates to a “string3” it’s value would be returned by the MAX() function. In the absence of a “string3” any “string2” will be returned.

Does case statement slow SQL?

2 Answers. The case statements are going to be much less of a factor than the joins in the WHERE clause. The main driver of performance in SQL is I/O — reading the data from disk. … You are doing nothing fancy in the case statement (such as a like or a subquery).

How do you use a case in a select 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 Insert statement as well.

Can I use CASE statement in where clause in Oracle?

Introduction to Oracle CASE expression You can use a CASE expression in any statement or clause that accepts a valid expression. For example, you can use the CASE expression in statements such as SELECT , UPDATE , or DELETE , and in clauses like SELECT , WHERE , HAVING , and ORDDER BY .

How does a case statement work?

The CASE statement chooses from a sequence of conditions, and executes a corresponding statement. The CASE statement evaluates a single expression and compares it against several potential values, or evaluates multiple Boolean expressions and chooses the first one that is TRUE .

Can we use CASE statement in update query?

The CASE expression allows a statement to return one of several possible results, depending on which of several condition tests evaluates to TRUE. You must include at least one WHEN clause within the CASE expression; subsequent WHEN clauses and the ELSE clause are optional.

How do you write a case statement in SQL stored procedure?

Case statement with simple expressionDECLARE @Name varchar(50)SET @Name = ‘Rohatash’SELECT.Case @Name.WHEN ‘Deepak’ THEN ‘Name Deepak’WHEN ‘Manoj’ THEN ‘Name Found Manoj’WHEN ‘Rohatash’ THEN ‘Name Found Rohatash’ELSE ‘Name not Found’More items…•

How can I return multiple values from a case statement in SQL?

Re: How to return multiple values using case in sql???WHEN THEN WHEN THEN ELSE END FROM

Can you put a case statement in a where clause?

Where Can I use a CASE 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.

Can we use subquery in case statement?

When a subquery is placed within the column list it is used to return single values. In this case, you can think of the subquery as a single value expression. The result returned is no different than the expression “2 + 2.” Of course, subqueries can return text as well, but you get the point!

Can we write CASE statement without else in SQL?

2 Answers. You can use a WHERE clause to restrict the output. Or if you wanted to showcase some other value instead of null use an else part inside the CASE statement.