SQL Server Where Clause

The SQL Server WHERE clause is used to specify a condition while fetching the data from a single table or by joining with multiple tables. If the given condition is satisfied, then only it returns a specific value from the table. It is used to extract only those records that fulfill a specified condition

The WHERE clause is not only used in the SELECT statement, but it is also used in the UPDATE, DELETE statement

Where Syntax 

SELECT column1, column2, columnN 
FROM [table_name]
WHERE [condition]

Where condition can also be specified with below operators.

Operator	Description
=	Equal
>	Greater than
<	Less than
>=	Greater than or equal
<=	Less than or equal
<>	Not equal. Note: In some versions of SQL this operator may be written as !=
BETWEEN	Between a certain range
LIKE	Search for a pattern
IN	To specify multiple possible values for a column

Where Clause example:

SQL requires single quotes around text values (most database systems will also allow double quotes).

However, numeric fields should not be enclosed in quotes:

USE AdventureWorks2017;
GO
SELECT Name, ProductNumber, ListPrice AS Price
FROM Production.Product 
WHERE ProductLine = 'R' AND DaysToManufacture < 4
ORDER BY Name ASC;

SELECT ID, NAME, SALARY 
FROM CUSTOMERS
WHERE SALARY > 2000;

SQL Server Select Statement

SQL Server select statement Retrieves rows from the database and enables the selection of one or many rows or columns from one or many tables in SQL Server. 

The full syntax of the SELECT statement is complex, but the main clauses can be summarized as:

SELECT select_list 

[ FROM table_source ] [ WHERE search_condition ]

[ GROUP BY group_by_expression ]

[ HAVING search_condition ]

[ ORDER BY order_expression [ ASC | DESC ] ]

The data returned is stored in a result table, called the result-set.

Select Statement Example:

USE AdventureWorks2017;
GO
SELECT *
FROM Production.Product
ORDER BY Name ASC;

 -- Alternate way.

USE AdventureWorks2017;
GO
SELECT p.*
FROM Production.Product AS p
ORDER BY Name ASC;

Adding Column name in select list

USE AdventureWorks2017;
GO
SELECT Name, ProductNumber, ListPrice AS Price
FROM Production.Product 
ORDER BY Name ASC;

USE AdventureWorks2017;
GO
SELECT Name, ProductNumber, ListPrice AS Price
FROM Production.Product 
WHERE ProductLine = 'R' 
AND DaysToManufacture < 4
ORDER BY Name ASC;