Using Wildcard Characters in SQL Statements

ID: Q98434

The information in this article applies to:

Microsoft Visual FoxPro for Windows, versions 3.0, 5.0, 6.0
Microsoft FoxPro for MS-DOS, versions 2.0, 2.5, 2.5a
Microsoft FoxPro for Windows, versions 2.5, 2.5a

SUMMARY

To broaden the selections of a structured query language (SQL) 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 statements are provided below. The examples use the CLIENTS.DBF file that is provided with FoxPro.

MORE INFORMATION

The following SELECT statement returns all the records from the CLIENTS.DBF file that contain an "N" as the first character in the STATE field. The SELECT statement lists the records from New York and New Jersey in a Browse window.


   SELECT * FROM clients WHERE state LIKE "N_"

The following SELECT statement lists all the records that have an "X" or a "Y" as the last character in the STATE field. The output will include records from New York and Texas.


   SELECT * FROM clients WHERE state LIKE "_Y" OR state LIKE "_X"

The following SELECT statement uses the percent sign and underscore to return all the records that have a CLIENT_ID number starting with "C" and that have a state abbreviation ending in "X". Note that the percent sign allows any string of characters to follow the "C". Conversely, the underscore allows the substitution of only a single character.


   SELECT * FROM CLIENTS WHERE CLIENTS.CLIENT_ID LIKE "C%" ;
   AND CLIENTS.STATE LIKE "_X"

To do a string search similar to the one performed by the $ function, use a statement like:


   SELECT * FROM CUSTOMER WHERE CUSTOMER.COMPANY LIKE "%X%"

This SELECT statement will find all companies with names that contain the letter "x".

REFERENCES

"Developer's Guide," version 2.0, page D7-9
"Developer's Guide," version 2.5, page D7-9
Visual FoxPro Help version 5.0; search on: "SELECT - SQL"
Visual FoxPro Help version 6.0: search on: "Tools"; Topic: menu pad

Additional query words: VFoxWin FoxDos FoxWin wild card select kbvfp300 kbvfp500 kbvfp600 search

Keywords : FxprgSql
Version : 2.00 2.50 2.50a | 2.50 2.50a 3.0
Platform : MS-DOS WINDOWS
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