WHERE Clause
Specifies which records from the tables listed in the FROM clause are affected by a SELECT, UPDATE, or DELETE statement.
Syntax
SELECT fieldlist
FROM tableexpression
WHERE criteria
A SELECT statement containing a WHERE clause has these parts:
| Part | Description |
|---|---|
| fieldlist | The name of the field or fields to be retrieved along with any field-name aliases, selection predicates (ALL, DISTINCT, DISTINCTROW, or TOP), or other SELECT statement options. |
| tableexpression | The name of the table or tables from which data is retrieved. |
| criteria | An expression that records must satisfy to be included in the query results. |
Remarks
The Microsoft Jet database engine selects the records that meet the conditions listed in the WHERE clause. If you do not specify a WHERE clause, your query returns all rows from the table. If you specify more than one table in your query and you have not included a WHERE clause or a JOIN clause, your query generates a Cartesian product of the tables.
WHERE is optional, but when included, follows FROM. For example, you can select all employees in the sales department (WHERE Dept = 'Sales') or all customers between the ages of 18 and 30 (WHERE Age Between 18 And 30).
If you do not use a JOIN clause to perform SQL join operations on multiple tables, the resulting Recordset object will not be updatable.
WHERE is similar to HAVING. WHERE determines which records are selected. Similarly, once records are grouped with GROUP BY, HAVING determines which records are displayed.
Use the WHERE clause to eliminate records you do not want grouped by a GROUP BY clause.
Use various expressions to determine which records the SQL statement returns. For example, the following SQL statement selects all employees whose salaries are more than $21,000:
SELECT LastName, Salary
FROM Employees
WHERE Salary > 21000;
A WHERE clause can contain up to 40 expressions linked by logical operators, such as And and Or.
When you enter a field name that contains a space or punctuation, surround the name with brackets ([ ]). For example, a customer information table might include information about specific customers :
SELECT [Customer’s Favorite Restarant]
When you specify the criteria argument, date literals must be in U.S. format, even if you are not using the U.S. version of the Microsoft® Jet database engine. For example, May 10, 1996, is written 10/5/96 in the United Kingdom and 5/10/96 in the United States. Be sure to enclose your date literals with the number sign (#) as shown in the following examples.
To find records dated May 10, 1996 in a United Kingdom database, you must use the following SQL statement:
SELECT *
FROM Orders
WHERE ShippedDate = #5/10/96#;
You can also use the DateValue function which is aware of the international settings established by Microsoft Windows®. For example, use this code for the United States:
SELECT *
FROM Orders
WHERE ShippedDate = DateValue('5/10/96');
And use this code for the United Kingdom:
SELECT *
FROM Orders
WHERE ShippedDate = DateValue('10/5/96');
Note If the column referenced in the criteria string is of type GUID, the criteria expression uses a slightly different syntax:
WHERE ReplicaID = {GUID {12345678-90AB-CDEF-1234-567890ABCDEF}}
Be sure to include the nested braces and hyphens as shown.