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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:
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.
16 kwi 2016 · However, given how the conditions are re-used in your UPDATE statement, you could also take a different approach altogether: represent the affected IDs and the new values as a derived table and use an update with a join: Tests AS old. INNER JOIN. SELECT 10 AS TestId, 25 AS TestSubId, 1000 AS TestScore, 2000 AS TestScore2. UNION ALL.
The UPDATE statement is used to modify the existing records in a table. SET column1 = value1, column2 = value2, ... Note: Be careful when updating records in a table! Notice the . WHERE clause in the UPDATE statement. The WHERE clause specifies which record (s) that should be updated.
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.
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); Here is SQLFiddle demo.
