WHERE (Transact-SQL)

Článok
09/03/2024

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW) SQL analytics endpoint in Microsoft Fabric Warehouse in Microsoft Fabric

Specifies the search condition for the rows returned by the query.

Transact-SQL syntax conventions

Syntax

[ WHERE <search_condition> ]

Arguments

< search_condition > Defines the condition to be met for the rows to be returned. There is no limit to the number of predicates that can be included in a search condition. For more information about search conditions and predicates, see Search Condition (Transact-SQL).

Examples

The following examples show how to use some common search conditions in the WHERE clause.

A. Finding a row by using a simple equality

-- Uses AdventureWorksDW  
  
SELECT EmployeeKey, LastName  
FROM DimEmployee  
WHERE LastName = 'Smith' ;

B. Finding rows that contain a value as part of a string

-- Uses AdventureWorksDW  
  
SELECT EmployeeKey, LastName  
FROM DimEmployee  
WHERE LastName LIKE ('%Smi%');

C. Finding rows by using a comparison operator

-- Uses AdventureWorksDW  
  
SELECT EmployeeKey, LastName  
FROM DimEmployee  
WHERE EmployeeKey  <= 500;

D. Finding rows that meet any of three conditions

-- Uses AdventureWorksDW  
  
SELECT EmployeeKey, LastName  
FROM DimEmployee  
WHERE EmployeeKey = 1 OR EmployeeKey = 8 OR EmployeeKey = 12;

E. Finding rows that must meet several conditions

-- Uses AdventureWorksDW  
  
SELECT EmployeeKey, LastName  
FROM DimEmployee  
WHERE EmployeeKey <= 500 AND LastName LIKE '%Smi%' AND FirstName LIKE '%A%';

F. Finding rows that are in a list of values

-- Uses AdventureWorksDW  
  
SELECT EmployeeKey, LastName  
FROM DimEmployee  
WHERE LastName IN ('Smith', 'Godfrey', 'Johnson');

G. Finding rows that have a value between two values

-- Uses AdventureWorksDW  
  
SELECT EmployeeKey, LastName  
FROM DimEmployee  
WHERE EmployeeKey Between 100 AND 200;

Zdieľať cez