To broaden the selections of a structured query language (SQL-SELECT) statement,
two wildcard characters, the percent sign (%) and the underscore (_), can
be used.
The percent sign is analogous to the asterisk (*) wildcard character used
with MS-DOS. The percent sign allows for the substitution of one or more
characters in a field.
The underscore is similar to the MS-DOS wildcard question mark
character. The underscore allows for the substitution of a single character
in an expression. Three examples showing the use of these characters in SQL-SELECT statements are provided below. The examples use the Customer.dbf file that
is included with Microsoft Visual FoxPro in the Home(2)+data folder.
The following SELECT-SQL statement returns all the records from the Customer.dbf
table that contain a "W" as the first character in the Regionabbreviation field. The
SELECT-SQL statement lists the records from "WY" and "WA" in a Browse
window.
SELECT * from customer WHERE Region like "W_"
The following SELECT-SQL statement lists all the records that have a "P" or a "C" as the last character in the Regionabbreviation field. The output includes
records from "SP" and "BC."
SELECT * from customer WHERE Region like "_P" OR region like "_C"
The following SELECT-SQL statement uses the percent sign and the underscore to
return all the records that have a Cust_ID that starts with "G" and
that have a Regionabbreviation field that ends with "P."
Note The percent sign
lets any string of characters follow the "G." Conversely, the
underscore permits the substitution of only a single character.
SELECT * FROM Customer WHERE cust_ID LIKE "G%" AND region LIKE "_P"
To do a string search similar to the one performed by the $ function, use a
statement like:
SELECT * from customer WHERE company like "%M%"
This SELECT-SQL statement finds all companies that have names that contain "M."
For additional information, see the Visual FoxPro Help files. Search for "SELECT - SQL."