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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.
29 maj 2013 · I have an update trigger which changes the value of state column to 0 based on some condition. I want to set the value of state column to 1 after 24 hours of modify_time, if it is still 0. I tried below method to test : CREATE EVENT myevent1. ON SCHEDULE AT current_timestamp + interval 1 minute.
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.
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:
14 mar 2012 · You can JOIN the contest and an inner-query on the answer table in the UPDATE clause and use MySQL's DATEDIFF to count the number-of-days since the answer was, well, answered: UPDATE tb_contest c JOIN (SELECT contest_id, MAX(date) AS date FROM tb_answer GROUP BY contest_id) AS a ON a.contest_id = c.id SET c.is_expire = 1 WHERE DATEDIFF(NOW(), a ...
11 mar 2015 · UPDATE user p. JOIN user_roles ur ON p.id = ur.user_id. SET ur.end_date = NOW() , p.end_date = NOW() , p.reason = "Retired". WHERE p.id = 5. AND ur.end_date IS NULL. I was thinking of doing something like this: IF EXISTS (SELECT id FROM user_roles.
