Using the FROM Clause

The FROM clause is required in every SELECT statement in which data is being retrieved from tables or views. Use the FROM clause to:

List the tables and views containing the columns referenced in the select list and in the WHERE clause. The table or view names can be aliased using the AS clause.
Join types. These are qualified by join conditions specified in the ON clause.

The FROM clause is a comma-separated list of table names, view names, and JOIN clauses.

Transact-SQL has extensions that support the specification of objects other than tables or views in the FROM clause. These other objects return a result set, or rowset in OLE DB terms, that form a virtual table. The SELECT statement then operates as if the result set were a table.

The FROM clause can specify:

One or more tables or views. For example:
```
SELECT *
FROM Shippers
```

Joins between two tables or views:

SELECT Cst.CustomerID, Cst.CompanyName, Cst.ContactName,
       Ord.ShippedDate, Ord.Freight 
FROM Northwind.dbo.Orders AS Ord
  JOIN
     Northwind.dbo.Customers AS Cst
  ON (Cst.CustomerID = Ord.CustomerID)

One or more derived tables, which are SELECT statements in the FROM clause referred to by an alias or a user-specified name. The result set of the SELECT in the FROM clause forms a table used by the outer SELECT statement. For example, this SELECT uses a derived table to find if any store carries all book titles in the pubs database:
```
SELECT ST.stor_id, ST.stor_name
FROM stores AS ST,
     (SELECT stor_id, COUNT(DISTINCT title_id) AS title_count
      FROM sales
      GROUP BY stor_id
     ) AS SA
WHERE ST.stor_id = SA.stor_id
  AND SA.title_count = (SELECT COUNT(*) FROM titles)
```
One or more tables or views from a linked server defined using sp_addlinkedserver. A linked server can be any OLE DB data source.
An OLE DB rowset returned by either the OPENROWSET or OPENQUERY functions.

The basis of Microsoft® SQL Server™ 2000 distributed queries are linked servers, OPENROWSET, and OPENQUERY. They provide the ability to query or modify data in any OLE DB data source as a part of Transact-SQL statements.

SELECT Statements Without FROM Clauses

The SELECT statements that do not require a FROM clause are those that are not selecting data from any tables in the database. These SELECT statements only select data from local variables or Transact-SQL functions that do not operate on a column, for example:

SELECT @MyIntVariable
SELECT @@VERSION
SELECT DB_ID('Northwind')

Using the FROM Clause

SELECT Statements Without FROM Clauses

See Also