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    <p>I must confess Im still a novice PHP/MySQL coder, but with many ideas; so my code is probably "dirty".</p> <p>So I solved the problem this way in order to move forward, but please better solutions are welcome. As for any strange syntax, I am using a database class built upon the PHP PDO because I am using many different RBDMS types on this project.</p> <p>For the $myQuery_start variable, I added the names of the other columns as well as sensors 1 to 3. <code><br /> $myQuery_start = "(SELECT sensor1, sensor2, sensor3 FROM ";<br/> $myQueryCount_start = "(SELECT COUNT(*) FROM ";<br/> $myQuery_stop = " WHERE robotID=".$robotID." AND timestamp BETWEEN ".$timeStampStart." AND ".$timeStampStop.")";<br /> </code> <br /> <code> $count_0 = DB::getDB("mysql", $myDB)->query($myQueryCount_start."table_0".$myQuery_stop)->fetchColumn();<br /> $count_1 = DB::getDB("mysql", $myDB)->query($myQueryCount_start."table_1".$myQuery_stop)->fetchColumn();<br /> $count_2 = DB::getDB("mysql", $myDB)->query($myQueryCount_start."table_2".$myQuery_stop)->fetchColumn();<br /> $count_3 = DB::getDB("mysql", $myDB)->query($myQueryCount_start."table_3".$myQuery_stop)->fetchColumn();<br /> $count_4 = DB::getDB("mysql", $myDB)->query($myQueryCount_start."table_4".$myQuery_stop)->fetchColumn();<br /> $count_5 = DB::getDB("mysql", $myDB)->query($myQueryCount_start."table_5".$myQuery_stop)->fetchColumn();<br /> </code> <br /> And now I check to see if UNION ALL needs to be appended to each table's query or not. No need to have a UNION ALL if there is no data record to attach in the next table. <br /> <code> $union_0 = (($count_1 + $count_2 + $count_3 + $count_4 + $count_5) > 0)?" UNION ALL ":"";<br /> $union_1 = (($count_2 + $count_3 + $count_4 + $count_5) > 0)?" UNION ALL ":"";<br /> $union_2 = (($count_3 + $count_4 + $count_5) > 0)?" UNION ALL ":"";<br /> $union_3 = (($count_4 + $count_5) > 0)?" UNION ALL ":"";<br /> $union_4 = (($count_5) > 0)?" UNION ALL ":"";<br /> </code> <br /> and now we build up the table queries and combine to form the full query<br /> <br /> <code> $query_0 = ($count_0 > 0)?$myQuery_start."ip_minute_stats_0".$myQuery_stop.$union_0:"";<br /> $query_1 = ($count_1 > 0)?$myQuery_start."ip_minute_stats_1".$myQuery_stop.$union_1:"";<br /> $query_2 = ($count_2 > 0)?$myQuery_start."ip_minute_stats_2".$myQuery_stop.$union_2:"";<br /> $query_3 = ($count_3 > 0)?$myQuery_start."ip_minute_stats_3".$myQuery_stop.$union_3:"";<br /> $query_4 = ($count_4 > 0)?$myQuery_start."ip_minute_stats_4".$myQuery_stop.$union_4:"";<br /> $query_5 = ($count_5 > 0)?$myQuery_start."ip_minute_stats_5".$myQuery_stop:""; </code> <br /> Then concatenated: <br /> <code> $myQuery = $query_0.$query_1.$query_2.$query_3.$query_4.$query_5; </code> <br /> And finally $myQuery is executed to produce all the data as required.</p> <p>At least this is roughly 8 times faster than the previous way I used UNION ALL, so I think this is valid. Any suggested further optimization?</p>
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    1. COPlease, more answers (or edits on the above answer) are welcome. My Boss still thinks this runs too slowly :(.I want to know I have tried my best before I move on. Thanks.
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