I have no option but to use dynamic sql i.e construct queries on fly because the final query depends on conditions,for example: 
if ($x>10) {
$query="(select Name from Customers where CustId='$custid')"
}
else {
 $query="(select Name from Sales where SalesId='$salesid')"
}

[download]

what I am worried about is 1.SQL injection, since I can't use placeholders and 2.performance, since the query won't be cached

What should I do about both of those points?

In reply to Dynamic SQL by Anonymous Monk

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