Monday, September 25, 2017

SELECT Statement

SELECT Statement

The SELECT statement Instructs the Microsoft Access database engine to return information from the database as a set of records.

Syntax

SELECT [predicate] { * | table.* | [table.]field1 [AS alias1] [, [table.]field2 [AS alias2] [, ...]]}
FROM tableexpression [, ...] [IN externaldatabase]
[WHERE... ]
[GROUP BY... ]
[HAVING... ]
[ORDER BY... ]
[WITH OWNERACCESS OPTION]

The SELECT statement has these parts:

Part

Description

predicate

One of the following predicates: ALL, DISTINCT, DISTINCTROW, or TOP. You use the predicate to restrict the number of records returned. If none is specified, the default is ALL.

*

Specifies that all fields from the specified table or tables are selected.

table

The name of the table containing the fields from which records are selected.

field1, field2

The names of the fields containing the data you want to retrieve. If you include more than one field, they are retrieved in the order listed.

alias1, alias2

The names to use as column headers instead of the original column names in table.

tableexpression

The name of the table or tables containing the data you want to retrieve.

externaldatabase

The name of the database containing the tables in tableexpression if they are not in the current database.

Remarks

To perform this operation, the Microsoft Access database engine searches the specified table or tables, extracts the chosen columns, selects rows that meet the criterion, and sorts or groups the resulting rows into the order specified.

SELECT statements do not change data in the database.

SELECT is usually the first word in an SQL statement. Most SQL statements are either SELECT or SELECT...INTO statements.

The minimum syntax for a SELECT statement is:

SELECT fields FROM table

You can use an asterisk (*) to select all fields in a table. The following example selects all of the fields in the Employees table:

SELECT * FROM Employees;

If a field name is included in more than one table in the FROM clause, precede it with the table name and the . (dot) operator. In the following example, the Department field is in both the Employees table and the Supervisors table. The SQL statement selects departments from the Employees table and supervisor names from the Supervisors table:

SELECT Employees.Department, Supervisors.SupvName FROM Employees INNER JOIN Supervisors WHERE Employees.Department = Supervisors.Department;

When a Recordset object is created, the Microsoft Access database engine uses the table's field name as the Field object name in the Recordset object. If you want a different field name or a name is not implied by the expression used to generate the field, use the AS reserved word. The following example uses the title Birth to name the returned Field object in the resulting Recordset object:

SELECT BirthDate AS Birth FROM Employees;

Whenever you use aggregate functions or queries that return ambiguous or duplicate Field object names, you must use the AS clause to provide an alternate name for the Field object. The following example uses the title HeadCount to name the returned Field object in the resulting Recordset object:

SELECT COUNT(EmployeeID) AS HeadCount FROM Employees;

You can use the other clauses in a SELECT statement to further restrict and organize your returned data. For more information, see the Help topic for the clause you are using.

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