Tutorial by Examples

Updating one row UPDATE customers SET email='[email protected]' WHERE id=1 This query updates the content of email in the customers table to the string [email protected] where the value of id is equal to 1. The old and new contents of the database table are illustrated below on the left an...

Consider a production table called questions_mysql and a table iwtQuestions (imported worktable) representing the last batch of imported CSV data from a LOAD DATA INFILE. The worktable is truncated before the import, the data is imported, and that process is not shown here. Update our production da...

If the ORDER BY clause is specified in your update SQL statement, the rows are updated in the order that is specified. If LIMIT clause is specified in your SQL statement, that places a limit on the number of rows that can be updated. There is no limit, if LIMIT clause not specified. ORDER BY and L...

In multiple table UPDATE, it updates rows in each specified tables that satisfy the conditions. Each matching row is updated once, even if it matches the conditions multiple times. In multiple table UPDATE, ORDER BY and LIMIT cannot be used. Syntax for multi table UPDATE is, UPDATE [LOW_PRIORITY]...

When updating multiple rows with different values it is much quicker to use a bulk update. UPDATE people SET name = (CASE id WHEN 1 THEN 'Karl' WHEN 2 THEN 'Tom' WHEN 3 THEN 'Mary' END) WHERE id IN (1,2,3); By bulk updating only one query can be sent to the ser...