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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.
26 lut 2014 · MySQL: Update table using subquery, Excel data. Here’s a snippet of SQL code and a procedure for updating a MySQL database table using a subquery and data from Microsoft Excel (or similar).
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:
29 kwi 2015 · IF EXISTS (select * from users where username = 'something') THEN. update users set id= 'some' where username = 'something'; ELSE. insert into users (username) values ('something'); END IF; end $$. delimiter ; and call it like this: call select_or_insert();
2 lut 2024 · MySQL will send an alert if a user tries inserting a record that already exists or has a duplicate PRIMARY KEY value. This article outlines the methods that can be used to correct this mistake and get a better result.
21 sie 2024 · Definition. The IF-THEN statement is used to execute a set of SQL statements based upon a pre-defined condition. When the condition checks to be TRUE, the statements between IF-THEN and ELSE execute. On the other hand, the statements (else-statements) between the ELSE and END IF execute.
1 cze 2015 · If you specify ON DUPLICATE KEY UPDATE, and a row is inserted that would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an UPDATE of the old row is performed. Please read URL for more details.
