如何使用php在一行中从mysql查询中获取单个字段？

Question

php and mysql...

the query:

$sql = "SELECT keyterm
        FROM keyterms
        WHERE keyterm_id = $keyterm_id";

$result = mysqli_query($dbcon,$sql); // returns a single result

fetch results:

$keyterm = mysqli_fetch_assoc($result);
$keyterm = $keyterm["keyterm"];

what is the equivalent of the last two lines in a single line?

Answer 1

You need to use fetch_object() because PHP allows you to chain the -> operator directly onto the return value of a function, which you cannot do with the [ ] operator.

$keyterm = $result->fetch_object()->keyterm;

Or, procedural style:

$keyterm = mysqli_fetch_object($result)->keyterm;

Answer 2

extract() ( take care ):

extract(mysqli_fetch_assoc($result));

You will get a warning when mysqli_fetch_assoc() returns FALSE (non-array). Field/Column name must be named as the variable.

Edit: Made it bold as some might have not read that.

Answer 3

If you only fetch a single column, you can also use:

 $keyterm = current(mysql_fetch_array($result));

Works since PHP5. It just gets the first entry from the array (whether indexed or associative), and assigns it to the variable. That's the cheapest option here.