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1 lut 2010 · Here's a query to update a table based on a comparison of another table. If record is not found in tableB, it will update the "active" value to "n". If it's found, will set the value to NULL. UPDATE tableA LEFT JOIN tableB ON tableA.id = tableB.id SET active = IF(tableB.id IS NULL, 'n', NULL)"; Hope this helps someone else.
Use the GREATEST() function (this needs a CAST() as well): UPDATE my_table SET comments = GREATEST(CAST(comments AS signed)-3, 0) WHERE something = 123; or the IF() function: UPDATE my_table SET comments = IF(comments>3, comments-3, 0) WHERE something = 123; or a CASE expression:
In this article, we would like to show you UPDATE query with IF condition in MySQL. Quick solution: UPDATE `table_name` SET `column_name` = IF(condition , if_true, if_false); Practical example. To show UPDATE query with IF condition, we will use the following users table:
11 lip 2024 · The IF () function in MySQL is a powerful tool that allows you to implement conditional logic directly within your SQL queries. It takes three parameters: a condition to evaluate, a value to return if the condition is true, and a value to return if the condition is false.
The IF statement can have THEN, ELSE, and ELSEIF clauses, and it is terminated with END IF. If a given search_condition evaluates to true, the corresponding THEN or ELSEIF clause statement_list executes. If no search_condition matches, the ELSE clause statement_list executes.
The MySQL UPDATE Statement. The UPDATE statement is used to modify the existing records in a table. UPDATE Syntax. UPDATE table_name. SET column1 = value1, column2 = value2, ... WHERE condition; Note: Be careful when updating records in a table! Notice the . WHERE clause in the UPDATE statement.
The WHERE clause, if given, specifies the conditions that identify which rows to update. With no WHERE clause, all rows are updated. If the ORDER BY clause is specified, the rows are updated in the order that is specified. The LIMIT clause places a limit on the number of rows that can be updated.
