What does delete query return in MySQL?

Single-Table Syntax. The DELETE statement deletes rows from tbl_name and returns the number of deleted rows.

What does delete query return?

The standard DELETE statement in SQL returns the number of deleted rows. In PostgreSQL you can make DELETE statement return something else.

What is delete query in MySQL?

What is the DELETE Query? MySQL Delete command is used to delete rows that are no longer required from the database tables. It deletes the whole row from the table and returns count of deleted rows. … The Delete query in MySQL can delete more than one row from a table in a single query.

Does SQL delete return value?

The optional RETURNING clause causes DELETE to compute and return value(s) based on each row actually deleted. Any expression using the table’s columns, and/or columns of other tables mentioned in USING, can be computed. The syntax of the RETURNING list is identical to that of the output list of SELECT.

What does MySQL query return?

For SELECT, SHOW, DESCRIBE, EXPLAIN and other statements returning resultset, mysql_query() returns a resource on success, or false on error. For other type of SQL statements, INSERT, UPDATE, DELETE, DROP, etc, mysql_query() returns true on success or false on error.

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What is the difference between truncate and delete?

Key differences between DELETE and TRUNCATE

The DELETE statement is used when we want to remove some or all of the records from the table, while the TRUNCATE statement will delete entire rows from a table. DELETE is a DML command as it only modifies the table data, whereas the TRUNCATE is a DDL command.

What will happen if you use delete command without the WHERE clause?

If you run a DELETE statement with no conditions in the WHERE clause, all of the records from the table will be deleted.

How do you use delete in SQL?

MySQL DELETE Statement

  1. DELETE FROM table_name WHERE condition;
  2. Example. DELETE FROM Customers WHERE CustomerName=’Alfreds Futterkiste’;
  3. DELETE FROM table_name;
  4. Example. DELETE FROM Customers;

How can I delete duplicate records in MySQL?

MySQL can remove duplicates record mainly in three ways.

  1. Delete Duplicate Record Using Delete Join. We can use the DELETE JOIN statement in MySQL that allows us to remove duplicate records quickly. …
  2. Delete Duplicate Record Using the ROW_NUMBER() Function. …
  3. DELETE Duplicate Rows Using Intermediate Table.

How delete a column in SQL?

In MySQL, the syntax for ALTER TABLE Drop Column is,

  1. ALTER TABLE “table_name” DROP “column_name”;
  2. ALTER TABLE “table_name” DROP COLUMN “column_name”;
  3. ALTER TABLE Customer DROP Birth_Date;
  4. ALTER TABLE Customer DROP COLUMN Birth_Date;
  5. ALTER TABLE Customer DROP COLUMN Birth_Date;

How do you write a delete query?

SQL DELETE Statement

  1. DELETE FROM table_name WHERE condition;
  2. Example. DELETE FROM Customers WHERE CustomerName=’Alfreds Futterkiste’;
  3. DELETE FROM table_name;
  4. Example. DELETE FROM Customers;

What is the function of on delete cascade?

Explanation: It is used to preserve referential integrity in the relation. When an attribute of a relation is the foreign key in another relation, deleting it causes referential integrity problems. The on delete cascade solves this problem by forcing us to delete the foreign key first.

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What are after triggers?

An after trigger runs after the corresponding insert, update, or delete changes are applied to the table. The WHEN condition can be used in an SQL trigger to specify a condition.

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