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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.
21 sie 2024 · MySQL offers conditional control flow with IF statements, allowing us to execute blocks of SQL code depending on whether a condition is true or false. In this article, We will learn about What is Decision-Making in MySQL with different statements along with examples and so on.
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 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.
11 mar 2015 · IF EXISTS (SELECT id FROM user_roles WHERE user_id = 5 AND end_date IS NULL) THEN 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 ELSE UPDATE user SET end_date = NOW() , reason = "Retired" WHERE id = 5 END IF
7 sty 2016 · UPDATE lfile SET name=LOAD_FILE('/home/ravi/Desktop/t') WHERE id=1; But it updates the name column with a NULL value. The function returns NULL when the file was not readable - check the privileges etc. Try select LOAD_FILE('/home/ravi/Desktop/t'); show warnings; to see what the function returns.
