Skip to main content

SQL Server - Delete Statement




Description

The SQL Server (Transact-SQL) DELETE statement is used to delete a single record or multiple records from a table in SQL Server.

Syntax

In the simplest form, the syntax for the DELETE statement in SQL Server (Transact-SQL) is:
DELETE FROM table
[WHERE conditions];
However, the full syntax for the DELETE statement in SQL Server (Transact-SQL) is:
DELETE [ TOP (top_value) [ PERCENT ] ]
FROM table
[WHERE conditions];

Parameters or Arguments

table
The table that you wish to delete records from.
WHERE conditions
Optional. The conditions that must be met for the records to be deleted.
TOP (top_value)
Optional. If specified, it will delete the top number of rows in the result set based on top_value. For example, TOP(10) would delete the top 10 rows matching the delete criteria.
PERCENT
Optional. If PERCENT is specified, then the top rows are based on a top_value percentage of the total result set (as specfied by the PERCENT value). For example, TOP(10) PERCENT would delete the top 10% of the records matching the delete criteria.

Note

  • You do not need to list fields in the SQL Server DELETE statement since you are deleting the entire row from the table.

Example - Using One condition

Let's look at a simple SQL Server DELETE query example, where we just have one condition in the DELETE statement.
For example:
DELETE FROM employees
WHERE first_name = 'Sarah';
This SQL Server DELETE example would delete all records from the employees table where the first_name is 'Sarah'.
You may wish to check for the number of rows that will be deleted. You can determine the number of rows that will be deleted by running the following SELECT statement before performing the delete.
SELECT count(*)
FROM employees
WHERE first_name = 'Sarah';

Example - Using Two conditions

Let's look at a SQL Server DELETE example, where we just have two conditions in the DELETE statement.
For example:
DELETE FROM employees
WHERE last_name = 'Johnson'
AND employee_id >= 80;
This SQL Server DELETE example would delete all records from the employees table where the last_name is 'Johnson' and the employee_id is greater than or equal to 80.
You may wish to check for the number of rows that will be deleted. You can determine the number of rows that will be deleted by running the following SELECT statement before performing the delete.
SELECT count(*)
FROM employees
WHERE last_name = 'Johnson'
AND employee_id >= 80;

Comments

Post a Comment

Popular posts from this blog

Variables

Variables The main way to store information in the middle of a PHP program is by using a variable. Here are the most important things to know about variables in PHP. All variables in PHP are denoted with a leading dollar sign ($). The value of a variable is the value of its most recent assignment. Variables are assigned with the = operator, with the variable on the left-hand side and the expression to be evaluated on the right. Variables can, but do not need, to be declared before assignment. Variables in PHP do not have intrinsic types - a variable does not know in advance whether it will be used to store a number or a string of characters. Variables used before they are assigned have default values. PHP does a good job of automatically converting types from one to another when necessary. PHP variables are Perl-like. PHP has a total of eight data types which we use to construct our variables − Integers  − are whole numbers, without a decima...
Post a Comment
Read more

SQL Server - INTERSECT Operator

Description The SQL Server (Transact-SQL) INTERSECT operator is used to return the records that are in common between two SELECT statements or data sets. If a record exists in one query and not in the other, it will be omitted from the INTERSECT results. It is the intersection of the two SELECT statements. Intersect Query Explanation:  The INTERSECT query will return the records in the blue shaded area. These are the records that exist in both Dataset1 and Dataset2. Each SELECT statement within the SQL Server INTERSECT must have the same number of columns in the result sets with similar data types. Syntax The syntax for the NTERSECT operator in SQL Server (Transact-SQL) is: SELECT expression1, expression2, ... expression_n FROM tables [WHERE conditions] INTERSECT SELECT expression1, expression2, ... expression_n FROM tables [WHERE conditions]; Parameters or Arguments expressions The columns or calculations that you wish to compare between the two SELECT ...
Post a Comment
Read more

About Application

The product is supposed to be an open source application, developed under the PRSC(Punjab Remote Sensing Centre)organization, for the usage of PUDA(Punjab Urban Planning and Development Authority ). It is An android based system implementing client-server model. The Po portal System provides simple mechanism for the Planning officer to share  truly verified report. The following are the main features that are included in the application are: Common platform support: Offers operating support for most of the known and commercial operating systems i.e. android operating system. Number of users being supported by the system: Though the number is precisely not mentioned but the system is able to support a large number of online users at a time. Search: search for the pending list of the cases assigned is generally by logging in to the application. Id system: provides each officer with a unique Id which is sent at the time of report submission. Verification  section: Verif...
Post a Comment
Read more