How To Delete All Rows a Table

Home > Oracle > SQL

Q

How To Delete All Rows a Table? - Oracle DBA FAQ - Understanding SQL DML 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:

SELECT COUNT(*) FROM fyi_links;
  COUNT(*)
----------
         3

TRUNCATE TABLE fyi_links;
Table truncated.

SELECT COUNT(*) FROM fyi_links;
  COUNT(*)
----------
         0

2007-04-21, 5651👍, 0💬

How To Select All Columns of All Rows from a Table
How To Select All Columns of All Rows from a Table? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements The simplest query statement is the one that selects all columns of all rows from a table: "SELECT * FROM table_name;". The (*) in the SELECT clause tells the query to return all columns.... 2007-04-21, 6922👍, 0💬

How To Delete Multiple Rows from a Table
How To Delete Multiple Rows from a Table? - Oracle DBA FAQ - Understanding SQL DML 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 the fyi_links table... 2007-04-21, 5914👍, 0💬

How To Select Some Columns from a Table
How To Select Some Columns from a Table? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements If you want explicitly tell the query to some columns, you can specify the column names in SELECT clause. The following select statement returns only two columns from the table "departments": SQL> S... 2007-04-21, 5726👍, 0💬

How To Delete All Rows a Table
How To Delete All Rows a Table? - Oracle DBA FAQ - Understanding SQL DML Statements 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 t... 2007-04-21, 5652👍, 0💬

How To Sort the Query Output
How To Sort the Query Output? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements If you want the returning rows to be sorted, you can specify a sorting expression in the ORDER BY clause. The following select statement returns rows sorted by the values in the "manager_id" column: SQL> SELEC... 2007-04-20, 5640👍, 0💬

How To Delete an Existing Row from a Table
How To Delete an Existing Row from a Table? - Oracle DBA FAQ - Understanding SQL DML 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: INSERT INTO fyi_links (url, id) VAL... 2007-04-21, 5610👍, 0💬

How To Use Existing Values in UPDATE Statements
How To Use Existing Values in UPDATE Statements? - Oracle DBA FAQ - Understanding SQL DML Statements If a row matches the WHERE clause in a UPDATE statement, existing values in this row can be used in expressions to provide new values in the SET clause. Existing values are represented by columns in ... 2007-04-21, 5545👍, 0💬

How To Use Values from Other Tables in UPDATE Statements
How To Use Values from Other Tables in UPDATE Statements? - Oracle DBA FAQ - Understanding SQL DML Statements If you want to update values in one with values from another table, you can use a subquery in the SET clause. The subquery should return only one row for each row in the update table that ma... 2007-04-21, 5485👍, 0💬

How To Select Some Rows from a Table
How To Select Some Rows from a Table? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements 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 following select state... 2007-04-21, 5425👍, 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.