How To Delete All Rows a Table

Home > MySQL > SQL

Q

How To Delete All Rows a Table? - MySQL FAQs - Understanding SQL INSERT, UPDATE and DELETE Statements

✍: FYIcenter.com

A

If you want to delete all rows from a table, you have two options:

Use the DELETE statement with no WHERE clause.
Use the TRUNCATE TABLE statement.

The TRUNCATE statement is more efficient the DELETE statement. The tutorial exercise shows you a good example of TRUNCATE statement:

mysql> SELECT COUNT(*) FROM fyi_links;
+----------+
| COUNT(*) |
+----------+
|        5 |
+----------+
1 row in set (0.08 sec)

mysql> TRUNCATE TABLE fyi_links;
Query OK, 0 rows affected (0.02 sec)

mysql> SELECT COUNT(*) FROM fyi_links;
+----------+
| COUNT(*) |
+----------+
|        0 |
+----------+
1 row in set (0.00 sec)

2007-05-11, 7951👍, 0💬

How To Select All Columns of All Rows from a Table
How To Select All Columns of All Rows from a Table? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY The simplest query statement is the one that selects all columns of all rows from a single table: "SELECT * FROM tableName;". The (*) in the SELECT clause tells the query to return all column... 2007-05-11, 7340👍, 0💬

How To Select Some Rows from a Table
How To Select Some Rows from a Table? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If you don't want select all rows from a table, you can specify a WHERE clause to tell the query to return only the rows that meets the condition defined in the WHERE clause. The WHERE clause condition is ... 2007-05-11, 7326👍, 0💬

What Happens If the UPDATE Subquery Returns No Rows
What Happens If the UPDATE Subquery Returns No Rows? - MySQL FAQs - Understanding SQL INSERT, UPDATE and DELETE Statements If you use a subquery to assign new values in the SET clause in an UPDATE statement, and the subquery returns no rows for an outer row, MySQL will provide a NULL value to the SE... 2007-05-11, 5685👍, 0💬

What Happens If the UPDATE Subquery Returns Multiple Rows
What Happens If the UPDATE Subquery Returns Multiple Rows? - MySQL FAQs - Understanding SQL INSERT, UPDATE and DELETE Statements If a subquery is used in a UPDATE statement, it must return exactly one row for each row in the update table that matches the WHERE clause. If it returns multiple rows, My... 2007-05-11, 5585👍, 0💬

How To Select Some Columns from a Table
How To Select Some Columns from a Table? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If you want explicitly tell the query to return some columns, you can specify the column names in the SELECT clause. The following select statement returns only two columns, "id" and "url" from the tabl... 2007-05-11, 5446👍, 0💬

How To Use Values from Other Tables in UPDATE Statements
How To Use Values from Other Tables in UPDATE Statements? - MySQL FAQs - Understanding SQL INSERT, UPDATE and DELETE Statements If you want to update values in one table with values from another table, you can use a subquery as an expression in the SET clause. The subquery should return only one row... 2007-05-11, 5443👍, 0💬

How To Create a Testing Table with Test Data
How To Create a Testing Table with Test Data? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If you want to follow the tutorial exercises presented in this collection, you need to create a testing table and insert some test data, as shown in the following sample script: mysql> CREATE TABLE... 2007-05-11, 5416👍, 0💬

How To Delete Multiple Rows from a Table
How To Delete Multiple Rows from a Table? - MySQL FAQs - Understanding SQL INSERT, UPDATE and DELETE Statements You can delete multiple rows from a table in the same way as deleting a single row, except that the WHERE clause will match multiple rows. The tutorial exercise below deletes 3 rows from t... 2007-05-11, 5367👍, 0💬

How To Delete an Existing Row from a Table
How To Delete an Existing Row from a Table? - MySQL FAQs - Understanding SQL INSERT, UPDATE and DELETE Statements If you want to delete an existing row from a table, you can use the DELETE statement with a WHERE clause to identify that row. Here is good sample of DELETE statements: mysql> INSERT INT... 2007-05-11, 5302👍, 0💬

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.