OR conditions in SQL Server

The OR condition in SQL Server (Transact-SQL) is used to check multiple conditions to see if any record in the returned result meets the condition. It is often used in SELECT, INSERT, UPDATE or DELETE commands.

Syntax OR condition

 WHERE 'điều kiện 1' 
 OR 'điều kiện 2' 
 … 
 OR 'điều kiện n' 

Variable name or variable value

Condition 1, Condition 2 . Condition n

One of these conditions must be met, the new record is selected

Note

1. The OR condition in SQL Server allows two or more conditions to be checked.
2. The OR condition in SQL Server needs to meet any of those conditions (from 1 to n), the new record is returned in the result set.

For example - SELECT 2 condition command

 SELE CT * 
 FROM nhanvien 
 WHRE ten = 'Sarah' 
 OR ho = 'J ohnson'; 

The result will be all employees named Sarah or they are Johnson. Because of using * in the SELECT statement, all fields in the table will be returned in the result set.

For example - SELECT 3 condition command

 SEL ECT ho, ten 
 FROM nhanvien 
 WHERE ho = 'Anderson' 
 OR bang = 'California' 
 OR nhanv ien_id = 50; 

In this example, the returned result is all the first and last names from the table, whose last name is Anderson or the state is California or the employee ID is 50.

Example - INSERT command

 INSERT INTO d anhba 
 (danhba_id, ho, ten) 
 SELECT nhanvien_id, ho, ten 
 FROM nhanvien 
 WHERE ho = 'Smith' 
 OR nhanvien_i d <10; 

This command inserts all the list of employee IDs, last names and names from the employee table if they are Smith or an employee ID less than 10.

Example - UPDATE command

 UPDATE en nhanvi 
 SET bang = 'Florida' 
 WHERE nhanvien_id < 1000 
 OR thanhpho = 'Mia mi'; 

In the example above, the OR condition will update the state value in the table to Florida if it is less than 1000 or has the city of Miami.

Example - DELETE command

 DELETE FROM nhanvien 
 WHERE ten = 'Joanne' 
 OR ten = 'Darlene'; 

The OR condition in this example will delete all employees in the table if the person's name is Joanne or Darlene.

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