How to Determine Number of Records Returned by SQL-SELECTLast reviewed: April 30, 1996Article ID: Q113808 |
The information in this article applies to:
SUMMARYYou can create generic SELECT statements that programmatically produce result sets of records to be output for viewing in a number of ways. However, in certain instances, a SELECT statement may not produce any records in the query based on the SQL criteria provided. To avoid having a program act upon an empty result, the system variable _TALLY can be evaluated immediately after a query has been executed in order to determine the number of records that have been selected. For more information about _TALLY, see the code example below.
MORE INFORMATIONThe following rudimentary example illustrates the usage of the _TALLY system variable:
* GENERIC.QPR
*
SET STATUS OFF && SET STATUS BAR OFF in FoxPro for Windows
fyl = GETFILE('DBF','Choose a database:')
USE (fyl)
LIST STRUCTURE
USE
ACCEPT 'Enter field list, separated by commas (or ENTER for all):' ;
TO flds
IF EMPTY(flds)
flds='*'
ENDIF
?
ACCEPT 'Enter conditions (or ENTER for none) ' TO cond
IF EMPTY(cond)
cond=''
ELSE
cond='WHERE '+cond
ENDIF
SELECT &flds FROM (fyl) &cond INTO CURSOR query NOCONSOLE
IF _TALLY>0
BROWSE
ELSE
WAIT WINDOW 'No matching records found...'
ENDIF
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Additional reference words: VFoxWin 3.00 FoxMac FoxDos FoxWin 2.00 2.50
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