MySQL Database Management System > MySQL Statements and Clauses

MySQL - Update and Delete Statements

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The UPDATE statement is used to change the contents of a table's existing records.

The SQL Delete command is part of the Data Manipulation Language, a SQL sub-language that allows database data to be modified. This command is used to delete records from a table that already exist. You can use this to delete certain records or all data from a table depending on a criterion.

UPDATE To change the rows in a table, use the MySQL command. You can use the update command to update a single field or multiple fields at once. It can also be used to insert values into a MySQL table from another table.

To avoid wasting too many resources, we must consider the updated table's lock escalation mode. Analyzing the execution strategy may aid in the resolution of update query performance problems. The table's unnecessary indexes can be removed.

  • The DELETE command deletes rows from table name and returns the number of rows that have been deleted.
  • The WHERE clause's (optional) constraints determine which rows to remove.
  • All rows are destroyed if the WHERE clause is not used.
  • The rows are eliminated in the order given if the ORDER BY clause is used.

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