SQL - Select doesn't retrieve results

问题

I'm using sqlsrv_num_rows in order to check if a user exists in the DB.

When i'm running the query in my DB i'm getting 1 result, but in my PHP I'm not getting anything (echo doesn't print anything). Why is that?

$query = "SELECT TOP 1 id, tourOp FROM users WHERE (valid = 1) AND (email = '".trim($_POST['email'])."') AND (password = '".trim($_POST['password'])."')";
$stmt  = sqlsrv_query( $conn, $query);      

echo "num: ".sqlsrv_num_rows( $stmt );

if (!sqlsrv_num_rows( $stmt )) {
    return (false); 
} else {

}

Example query

SELECT TOP 1 id, name FROM users WHERE (valid = 1) AND (email = 'roi@some_email.com') AND (password = '8521')

I'm using PHP and MSSQL.

回答1:

Explanations:

Function sqlsrv_num_rows() requires a client-side, static, or keyset cursor, and will return false if you use a forward cursor or a dynamic cursor (the default cursor is forward cursor). Execute sqlsrv_query() with additional $options parameter and set the appropriate cursor type with "Scrollable" => SQLSRV_CURSOR_KEYSET
Use parameterized statements. Function sqlsrv_query() does both statement preparation and statement execution and can be used to execute parameterized queries.
If you want to check if the result set has one or more rows, you may use sqlsrv_has_rows().

Example, based on your code:

<?php
$query = "
    SELECT TOP 1 id, tourOp 
    FROM users 
    WHERE (valid = 1) AND (email = ?) AND (password = ?)";
$params = array(trim($_POST['email']), trim($_POST['password']));
$options = array("Scrollable" => SQLSRV_CURSOR_KEYSET);
$stmt = sqlsrv_query( $conn, $query, $params, $options);      
if ($exec === false){
    echo print_r( sqlsrv_errors()); 
    echo "<br>";
    return (false);
}

$count = sqlsrv_num_rows($stmt);
if ($count === false) {
    echo print_r( sqlsrv_errors()); 
    echo "<br>";
    return (false);
} else {
    echo "num: ".$count;
}
?>

Notes:

Do not send user credentials in plain text.

来源：https://stackoverflow.com/questions/59037149/sql-select-doesnt-retrieve-results

标签

php

sql-server

sqlsrv