Insert data array in SQL after searching from another SQL table - php

Question

I have an array $members that contains some ID(maximum 6 in number) from the table users. Using the following code, I loop through each index of $members, search for the details and store them in another array.
foreach($members as $key=>$value){
$res = mysql_query("SELECT id,name,email FROM users WHERE id='$value'");
if ($res === false) {
echo mysql_error();
die;
}
$row = mysql_fetch_assoc($res);
if($row['id'])
{
$members_name[]=$row['name'];//array for name
}
}
Now I want to insert the ID & names that are stored in the array into another TABLE register in the following format:
(The left side are the rows in my TABLE register)
mem_0_id-->$members[0]
mem_0_name-->$members_name[0]
mem_1_id-->$members[1]
mem_1_name-->$members_name[1]
mem_2_id-->$members[2]
mem_2_name-->$members_name[2]
mem_3_id-->$members[3]
mem_3_name-->$members_name[3]
mem_4_id-->$members[4]
mem_4_name-->$members_name[4]
How can I insert in this way? using just a single INSERT statement?

Answer 1

haven't tried this, but here is my answer anyway :)
$query = "INSERT INTO register(id, name) VALUES ($members[0], $members_name[0])";
for($i=1; $i<count($members); $i++)
{
$query .= ", ($members[$i], $members_name[$i])";
}
then try to execute the query..

Answer 2

Do you do anything else with the array, or are you just retrieving it from one table in order to insert it into another?
If so then you can do the whole thing like this.
$memberIds = implode(',', $members); // comma separated list of member ids
$query = "insert into register (id, name) select id, name from users where id in ($memberIds)";
mysql_query($query); // this will select and insert in one go
If you do need to keep the array in memory, then it's still a good idea to get it all out at once
$memberIds = implode(',', $members); // comma separated list of member ids
$query = "select id, name from users where id in ($memberIds)";
$res = mysql_query($query);
while ($row = mysql_fetch_assoc($res)) {
$memberData[] = $row;
}
That's because running a query inside a loop is very bad for performance. Every time you run a query there is an overhead, so getting all the data at once means you pay this overhead once rather than multiple times.
Then you can build a statement to insert multiple rows:
$sql = "insert into register (id, name) values ";
$sql .= "(" . $memberData[0]['id'] . "," . $memberData[0]['name'] . ")";
for($i = 1; $i < count($memberData); $i++) {
$sql .= ",(" . $memberData[$i]['id'] . ",'" . $memberData[$i]['name'] . "')";
}
mysql_query($sql);
It's a bit nasty because of the commas and quotes but if I've done it correctly then if you do
echo $sql;
you should get something like
insert into register (id, name) values (1, 'john'), (2, 'jane'), (3, 'alice');
You can see that the first way, where you select and insert in one statment, is a lot nicer and easier so if you don't do anything else with the array then I highly recommend doing it that way.