08-03-2007
Optimizing query
Hi All,
My first thread to this sub-forum and first thread of this sub-forum
Here it is,
Am trying to delete duplicates from a table retaining just 1 duplicate value out of the duplicate records
for example : from n records of a table out of which x are duplicates, I want to remove x - 1 records retaining 1 record from the x duplicates
This is the query am using,
but I think this could still be optimized for this query really takes time for huge dumps.
DELETE FROM tableA
WHERE rowid not in
(SELECT MIN(rowid) FROM tableA GROUP BY column1)
Oracle 9i
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LEARN ABOUT PHP
sybase_affected_rows
SYBASE_AFFECTED_ROWS(3) SYBASE_AFFECTED_ROWS(3)
sybase_affected_rows - Gets number of affected rows in last query
SYNOPSIS
int sybase_affected_rows ([resource $link_identifier])
DESCRIPTION
sybase_affected_rows(3) returns the number of rows affected by the last INSERT, UPDATE or DELETE query on the server associated with the
specified link identifier.
This command is not effective for SELECT statements, only on statements which modify records. To retrieve the number of rows returned from
a SELECT, use sybase_num_rows(3).
PARAMETERS
o $link_identifier
- If the link identifier isn't specified, the last opened link is assumed.
RETURN VALUES
Returns the number of affected rows, as an integer.
EXAMPLES
Example #1
Delete-Query
<?php
/* connect to database */
sybase_connect('SYBASE', '', '') or
die("Could not connect");
sybase_select_db("db");
sybase_query("DELETE FROM sometable WHERE id < 10");
printf("Records deleted: %d
", sybase_affected_rows());
?>
The above example will output:
Records deleted: 10
SEE ALSO
sybase_num_rows(3).
PHP Documentation Group SYBASE_AFFECTED_ROWS(3)