MySQL: multiple search/select queries at the same time? - php

Question

I have a question on how to go about the next phase of a project I am working on.
Phase I:
create a php script that scraped directory for all .txt file..
Open/parse each line, explode into array...
Loop through array picking out pieces of data that were needed and INSERTING everything into the database (120+ .txt files & 100k records inserted)..
this leads me to my next step,
Phase II:
I need to take a 'list' of several 10's of thousand of numbers..
loop through each one, using that piece of data (number) as the search term to QUERY the database.. if a match is found I need to grab a piece of data in a different column of the same record/row..
General thoughts/steps I plan to take
scrape directory to find 'source' text file.
open/parse 'source file'.... line by line...
explode each line by its delimiting character.. and grab the 'target search number'
dump each number into a 'master list' array...
loop through my 'master list' array.. using each number in my search (SELECT) statement..
if a match is found, grab a piece of data in another column in the matching/returned row (record)...
output this data.. either to screen or .txt file (havent decided on that step yet,..most likely text file through each returned number on a new line)
Specifics:
I am not sure how to go about doing a 'multiple' search/select statement like this?
How can I do multiple SELECT statements each with a unique search term? and also collect the returned column data?
is the DB fast enough to return the matching value/data in a loop like this? Do I need to wait/pause/delay somehow for the return data before iterating through the loop again?
thanks!
current function I am using/trying:
this is where I am currently:
$harNumArray2 = implode(',', $harNumArray);
//$harNumArray2 = '"' . implode('","', $harNumArray) . '"';
$query = "SELECT guar_nu FROM placements WHERE har_id IN ($harNumArray2)";
echo $query;
$match = mysql_query($query);
//$match = mysql_query('"' . $query . '"');
$results = $match;
echo("<BR><BR>");
print_r($results);
I get these outputs respectively:
Array ( [0] => sample_source.txt )
Total FILES TO GRAB HAR ID's FROM: 1
TOAL HARS FOUND IN ALL FILES: 5
SELECT guar_nu FROM placements WHERE har_id IN ("108383442","106620416","109570835","109700427","100022236")
&
Array ( [0] => sample_source.txt )
Total FILES TO GRAB HAR ID's FROM: 1
TOAL HARS FOUND IN ALL FILES: 5
SELECT guar_nu FROM placements WHERE har_id IN (108383442,106620416,109570835,109700427,100022236)
Where do I stick this to actually execute it now?
thanks!
update:
this code seems to be working 'ok'.. but I dont understand on how to handle the retirned data correctly.. I seem to only be outputting (printing) the last variable/rows data..instead of the entire list..
$harNumArray2 = implode(',', $harNumArray);
//$harNumArray2 = '"' . implode('","', $harNumArray) . '"';
//$query = "'SELECT guar_num FROM placements WHERE har_id IN ($harNumArray2)'";
$result = mysql_query("SELECT har_id, guar_num FROM placements WHERE har_id IN (" . $harNumArray2 . ")")
//$result = mysql_query("SELECT har_id, guar_num FROM placements WHERE har_id IN (0108383442,0106620416)")
or die(mysql_error());
// store the record of the "example" table into $row
$row = mysql_fetch_array($result);
$numRows = mysql_num_rows($result);
/*
while($row = #mysql_fetch_assoc($result) ){
// do something
echo("something <BR>");
}
*/
// Print out the contents of the entry
echo("TOTAL ROWS RETURNED : " . $numRows . "<BR>");
echo "HAR ID: ".$row['har_id'];
echo " GUAR ID: ".$row['guar_num'];
How do I handle this returned data properly?
thanks!

Answer 1

I don't know if this answers your question but I think you're asking about sub-queries. They're pretty straightforward and just look something like this
SELECT * FROM tbl1 WHERE id = (SELECT num FROM tbl2 WHERE id = 1);
That will only work if there is one unique value to that second subquery. If it returns multiple rows it will return a parse error. If you have to select multiple rows research JOIN statements. This can get you started
http://www.w3schools.com/sql/sql_join.asp

Answer 2

I am not sure how to go about doing a 'multiple' search/select statement like this?
With regards to a multiple select, (and I'll assume that you're using MySQL) you can perform that simply with the "IN" keyword:
for example:
SELECT *
FROM YOUR_TABLE
WHERE COLUMN_NAME IN (LIST, OF, SEARCH, VALUES, SEPARATED, BY COMMAS)
EDIT: following your updated code in the question.
just a point before we go on... you should try to avoid the mysql_ functions in PHP for new code, as they are about to be deprecated. Think about using the generic PHP DB handler PDO or the newer mysqli_ functions. More help on choosing the "right" API for you is here.
How do I handle this returned data properly?
For handling more than one row of data (which you are), you should use a loop. Something like the following should do it (and my example will use the mysqli_ functions - which are probably a little more similar to the API you've been using):
$mysqli = mysqli_connect("localhost", "user", "pass");
mysqli_select_db($mysqli, "YOUR_DB");
// make a comma separated list of the $ids.
$ids = join(", ", $id_list);
// note: you need to pass the db connection to many of these methods with the mysqli_ API
$results = mysqli_query($mysqli, "SELECT har_id, guar_num FROM placements WHERE har_id IN ($ids)");
$num_rows = mysqli_num_rows($results);
while ($row = mysqli_fetch_assoc($results)) {
echo "HAR_ID: ". $row["har_id"]. "\tGUAR_NUM: " . $row["guar_num"] . "\n";
}
Please be aware that this is very basic (and untested!) code, just to show the bare minimum of the steps. :)