koreantore.blogg.se - Postgresql if then else

The function returns if_true_expr if expr evaluates to true (it is not NULL). The IF function returns a value for a specified condition and has the following syntax: IF(expr,if_true_expr,if_false_expr) Pay attention that the IF function is not the same as the IF statement. SET Message = 'We have NULL, but result is valid!!!' ĭELIMITER MySQL IF function: definition and examples What is MySQL function?įunction in MySQL comprises a set of SQL statements with certain parameters that perform a task or operation and return a value as a result.įor example, the MySQL Version() function returns the current version of the MySQL database. SELECT COUNT(*) INTO sum_null FROM TASKS WHERE STATUS IS NULL If the value does not satisfy two previous conditions, there will the message “We do not have rows with NULL!!!” in the output.If the sum of all empty values in the STATUS column is more than 3, you will see “We have NULL, but result is valid!!!”.

If the sum of all empty values in the STATUS column is less than 3, the message “We have rows with NULL!!!” will be displayed.

Using the IF-THEN-ELSEIF-ELSE statement, we set multiple conditions: SET Message = 'We do not have rows with NULL!!!' SELECT COUNT(*) INTO sum_null FROM TASKS WHERE STATUS IS NOT NULL

If the sum of all completed records in the STATUS column isn’t 0, you will see “We do not have rows with NULL!!!” in the output.

If the sum of all completed records in the STATUS column is 0, there will be the message “We have rows with NULL!!!”.

In this IF-THEN-ELSE statement, we specify two conditions: SET Message = 'We have rows with NULL!!!' SELECT COUNT(*) INTO sum_null FROM TASKS WHERE status IS NULL In the statement below, we declare the following condition using IF-THEN: if the sum of all empty entries in the STATUS column is more than 0, then in the output you will see the message “We have rows with NULL!!!” DELIMITER $$ĭECLARE sum_null DECIMAL(10,2) DEFAULT 0 In this section, we are going to review examples of the IF statements usage.

false – the next elseif-condition will be evaluatedĪnd if there is no true condition both in the IF-THEN and in the ELSEIF-THEN blocks, else-statements will be applied.

true – elseif-statements will be executed.false – elseif-condition will be evaluated.Let’s review each block. If a condition in IF-THEN is: The syntax is given below: IF condition THEN Using IF-THEN-ELSEIF-ELSE, you can run statements based on several conditions. false – statements following the ELSE and END-IF will be executed.true – statements between IF-THEN and ELSE will be executed.The syntax looks as follows: IF condition THEN To execute statements when a condition in the IF block does not evaluate to true, you can use IF-THEN-ELSE. false – statements following the END-IF block will be applied.true – statements between IF-THEN and END-IF will be executed.Here is the statement syntax: IF condition THEN You can use IF-THEN to run a collection of SQL queries based on a condition. There are three types of MySQL IF statements: The IF statement allows you to verify a condition. Example 4: display N/A instead of NULL using MySQL IF function.Example 1: MySQL IF function with aggregate functions.MySQL IF function: definition and examples.MySQL IF statements: syntax and examples.Also, we will review other MySQL functions. In this article, we will explain their diversities and show usage examples. There are two types of IFs in MySQL: the IF statement and the IF function.