write a case statement in sql

The SQL CASE Expression. The CASE expression goes through conditions and returns a value when the first condition is met (like an if-then-else statement). So, once a condition is true, it will stop reading and return the result. If no conditions are true, it returns the value in the ELSE clause.. If there is no ELSE part and no conditions are true, it returns NULL.

Here are the CASE statement examples from the PostgreSQL docs (Postgres follows the SQL standard here):. SELECT a, CASE WHEN a=1 THEN 'one' WHEN a=2 THEN 'two' ELSE 'other' END FROM test; or. SELECT a, CASE a WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 'other' END FROM test;

Before I go into details on how CASE works, take a look at the syntax of the CASE statement: CASE WHEN <condition> THEN <value>, WHEN <other condition> THEN <value> ELSE <value> END AS <column name>. Let's look at a practical example of a simple CASE statement. Here is the order_summary table: order_id.

To display a value based on your specific condition (s), you need to write a CASE statement. The syntax is: If condition_1 is met, then the retrieved value is value_1. If not, then the database checks for condition_2. If condition_2 is true, then the retrieved value is value_2. If neither of these conditions is met, SQL checks for the remaining ...

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 this article, we would explore the CASE statement and its various use cases. Suppose you have a table that stores the ProductID for ...

The CASE expression compares an expression to a set of expression (when_expression_1, when_expression_2, when_expression_3, …) using the equality operator (=). If you want to use other comparison operators such as greater than (>), less than (<), etc., you use the searched CASE expression. The CASE statement returns the result_1, result_2, or ...

The CASE expression can't be used to control the flow of execution of Transact-SQL statements, statement blocks, user-defined functions, and stored procedures. For a list of control-of-flow methods, see Control-of-Flow Language (Transact-SQL). The CASE expression evaluates its conditions sequentially and stops with the first condition whose ...

Understanding CASE WHEN Syntax. Basic Syntax: CASE WHEN THEN. CASE WHEN THEN ELSE. Multiple THENs in CASE WHEN. Examples of Using CASE WHEN in Data Analysis. Example 1: Categorizing Data. Example 2: Handling NULL Values. Example 3: Creating Aggregated Columns. Example 4: Marketing Analysis.

With SQL, you can do this using the CASE statement. You use the CASE keyword together with the WHEN clause to execute a block of conditional statement code. You use a THEN statement to return the result of the expression. If none of the conditions are met, then you use a final ELSE clause to return a fallback result.

The SQL CASE statement is a powerful tool that allows you to perform conditional logic in your SQL queries. The statement is used to evaluate a condition or set of conditions and return a value based on the result of that evaluation. Syntax.

The SQL CASE statement evaluates a list of conditions and adds a column with values based on the condition. For example, -- add a new column 'order_volume' in the Orders table -- and flag any order greater than 10000 as 'Large Order' -- and smaller than 10000 as 'Small Order' SELECT *, CASE WHEN amount >= 10000 THEN 'Large Order' WHEN amount < 10000 THEN 'Small Order' END AS 'order_volume ...

SQL CASE Statement Syntax. The syntax of the SQL CASE expression is: CASE [expression] WHEN condition_1 THEN result_1. WHEN condition_2 THEN result_2 ... WHEN condition_n THEN result_n. ELSE result. END case_name. The CASE statement can be written in a few ways, so let's take a look at these parameters.

How to Write a Case Statement in SQL. Maybe you would like to give your students a message regarding the status of their assignment. To get the status, you could just select the submitted_essay column, but a message that just says TRUE or FALSE is not especially human-readable.. Instead, you could use a CASE statement and print out different messages depending on whether submitted_essay is ...

The first technique involves using COALESCE or NULLIF functions in conjunction with case statements. These functions allow developers to replace NULL values with default values or transform non-NULL values into NULLs. Here's an example of using COALESCE: SELECT employee_id, COALESCE(salary_bonus, 0) AS bonus.

The CASE statement can be used in SQL Server (Transact-SQL). You could use the CASE statement in a SQL statement as follows: (includes the expression clause) SELECT contact_id, CASE website_id WHEN 1 THEN 'TechOnTheNet.com' WHEN 2 THEN 'CheckYourMath.com' ELSE 'BigActivities.com' END FROM contacts; Or you could write the SQL statement using the ...

We can use the CASE statement to give each student a grade, which we will add in a new column named grade. Let's first write the CASE statement, in which we will write the breakdown for each grade. When score is 94 or higher, the row will have the value of A. If the score is instead 90 or higher it will have the value of A-, and so on.

The SQL CASE statement is a conditional expression that allows for the execution of different queries based on specified conditions. There should always be a SELECT in the CASE statement. END ELSE is an optional component but WHEN THEN these cases must be included in the CASE statement. We can make any conditional statement using any ...

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. For instance, let's see how we can reference the "AdventureWorks2012" database and show an example of a SQL Case statement.

As you write an SQL query, you may need to get values from multiple columns and change values from one form to another. The simple way to achieve this goal is to add a CASE expression to your SELECT statement. In this article, we'll introduce you to the syntax, formats, and uses of the CASE expression.. The CASE expression is a conditional expression: it evaluates data and returns a result.

The SQL CASE statement specifies a conditional expression to perform different actions depending on the input expression value. The syntax for the CASE statement in a SQL database is: ... CASE is an expression. You can't write: CASE WHEN X = 1 THEN UPDATE ... WHEN X = 2 THEN INSERT ... ELSE DELETE ... END which would be valid if CASE was a ...

Here are 3 different ways to apply a case statement using SQL: (1) For a single condition: Copy. CASE WHEN condition_1 THEN result_1 ELSE result_2 END AS new_field_name. (2) For multiple conditions using AND: Copy. CASE WHEN condition_1 AND condition_2 THEN result_1 ELSE result_2 END AS new_field_name. (3) For multiple conditions and results:

The CASE statement cannot have an ELSE NULL clause, and it is terminated with END CASE instead of END . For the first syntax, case_value is an expression. This value is compared to the when_value expression in each WHEN clause until one of them is equal. When an equal when_value is found, the corresponding THEN clause statement_list executes.

I'm writing an SQL Query, where a few of the columns returned need to be calculated depending on quite a lot of conditions. I'm currently using nested case statements, but its getting messy. Is there a better (more organised and/or readable) way? (I am using Microsoft SQL Server, 2005)

I would like to return multiple values in my case statement, such as : CASE. WHEN <condition 1> THEN <value1=a1, value2=b1>. WHEN <condition 2> THEN <value1=a2, value2=b2>. ELSE <value1=a3, value3=b3>. END. Of course I can write the case condition multiple times, each time return one value. However, as I have many condition need to fit, say 100.

In PostgreSQL and MySQL databases, we can use POSITION () to search for a word: SELECT * FROM Product. WHERE POSITION ( 'Milk' IN description) > 0 OR POSITION ( 'Dark' IN description) > 0 ; The POSITION () function returns the index of the provided substring in the given column and 0 if it doesn't exist.