What is the correct syntax for the following/

PHP Code:

$sql="SELECT fam_ui FROM fam_data WHERE fam_i = $fam_i and in_i = $in_i";

$sql2="SELECT ui FROM raw_allele WHERE fam_ui++d_no == $fam_ui_result ++ $matches"; 


http://www.w3schools.com/sql/sql_where.asp

and don't mix php variables and sql or you'll get confused with bigger queries and with the creation of more complex queries based on different conditions.

Anyway the first sql query could be correct if $fam_i and $in_i are integer values, the second query is wrong.
Concatenate variables and strings with the .(dot) to create any kind of string,
that's the best way to have a cleaner and more readable code that can be parsed faster by php.

$sql="SELECT `fam_ui` FROM `fam_data` WHERE `fam_i` = '$fam_i and in_i = $in_i' ";
if the fields are anything other than integer

j2be: The dot . operator will concatenate two PHP variables, but in order to concatenate two SQL fields during the query you'll need to use the SQL function CONCAT(string1,string2)

PHP Code:

$sql2="SELECT ui FROM raw_allele WHERE CONCAT(fam_ui,d_no) = " . $fam_ui_result . $matches; 


rungss: you are missing some quotes in the where clause of the query.

PHP Code:

$sql="SELECT `fam_ui` FROM `fam_data` WHERE `fam_i` = '$fam_i' and in_i = '$in_i' "; 


Or if you want to separate the PHP and SQL:

PHP Code:

$sql="SELECT `fam_ui` FROM `fam_data` WHERE `fam_i` = '" . $fam_i . "' and in_i = '" . $in_i' "; 


Personally I use a combination of PHP variables inside and outside the string - sometimes the variable cause confusion especially if they are parts of an array. Other times the quotes get confusing as to what is SQL and what is the edge of the PHP string.

Originally Posted by rungss

$sql="SELECT `fam_ui` FROM `fam_data` WHERE `fam_i` = '$fam_i and in_i = $in_i' ";
if the fields are anything other than integer

I'm talking ONLY about strings and variables concatenation in php!