What is the command to update table data in mysql?

The command used to update table data in MySQL is UPDATE. The update syntax is: UPDATE table_name SET column1 = value1, column2 = value2, ... WHERE condition; where condition specifies the update condition, and only rows that meet the condition are updated. Other considerations include using the WHERE clause to update all rows if no condition is specified, using indexed columns to improve performance, UPDATE to return the number of affected rows, and syntax updates to UPDATE ... SET ... RETURNING *; The data is returned

The command for updating table data in MySQL

The command for updating table data in MySQL is UPDATE.

UPDATE syntax

<code class="sql">UPDATE table_name SET column1 = value1, column2 = value2, ...
WHERE condition;</code>

Among them:

• table_name: The name of the table to be updated.
• column1, column2,...: Column names to be updated.
• value1, value2,...: The value to be updated.
• condition (optional): Specify the update condition and only update rows that meet the condition.

Example

The following example updates the salary of an employee named "John Doe" in table employees to 50,000:

<code class="sql">UPDATE employees SET salary = 50000 WHERE name = "John Doe";</code>

Other Notes

• When using the WHERE clause, if no condition is specified, all rows in the table will be updated.
• In order to improve performance, it is recommended to use index columns in the WHERE clause.
• UPDATE The command returns the number of rows affected, which if 0 means no rows were updated.
• You can also use the UPDATE ... SET ... RETURNING *; syntax to update data and return the updated rows.

The above is the detailed content of What is the command to update table data in mysql?. For more information, please follow other related articles on the PHP Chinese website!