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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.
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:
Use IF...THEN...ELSEIF...ELSE statement to evaluate multiple conditions sequentially and execute corresponding blocks of statements based on the first true condition, with an optional block of statements to execute if none of the conditions is true.
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.
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 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.
23 cze 2013 · UPDATE relation SET name1 = CASE WHEN userid1 = 3 THEN 'jack' ELSE name1 END, name2 = CASE WHEN userid2 = 3 THEN 'jack' ELSE name2 END WHERE (userid1 = 3 AND userid2 = 4) OR (userid1 = 4 AND userid2 = 3);
