php mysqli prepared statements select - php

Question

Trying to get a function working to create simple CRUD "Select" with multiple parameters to any table. I think I got the hardest part, but couldn't fetch the data right now. Maybe I'm doing something wrong I can't figure out.
My prepared statement function:
function prepared_query($mysqli, $sql, $params, $types = ""){
$types = $types ?: str_repeat("s", count($params));
if($stmt = $mysqli->prepare($sql)) {
$stmt->bind_param($types, ...$params);
$stmt->execute();
return $stmt;
} else {
$error = $mysqli->errno . ' ' . $mysqli->error;
error_log($error);
}
}
The query creator:
function create_select_query($table, $condition = "", $sort = "", $order = " ASC ", $clause = ""){
$table = escape_mysql_identifier($table);
$query = "SELECT * FROM ".$table;
if(!empty($condition)){
$query .= create_select_query_where($condition,$clause);
}
if(!empty($sort)){
$query .= " ORDER BY ".$sort." $order";
}
return $query;
}
The helper function to create the WHERE clause:
function create_select_query_where($condition,$clause){
$query = " WHERE ";
if(is_array($condition)){
$pair = array();
$size = count($condition);
$i = 0;
if($size > 1){
foreach($condition as $field => $val){
$i++;
if($size-1 == $i){
$query .= $val." = ? ".$clause. " ";
}else{
$query .= $val." = ? ";
}
}
}else{
foreach($condition as $field => $val){
$query .= $val." = ? ";
}
}
}else if(is_string($condition)){
$query .= $condition;
}else{
$query = "";
}
return $query;
}
The select function itself:
function crud_select($conn, $table, $args, $sort, $order, $clause){
$sql = create_select_query($table, array_keys($args),$sort, $order, $clause);
print_r($sql);
if($stmt = prepared_query($conn, $sql, array_values($args))){
return $stmt;
}else{
$errors [] = "Something weird happened...";
}
}
When I create the query, it seems to be OK but can't fetch the data. If I create an array with only one argument the query translates into:
SELECT * FROM `teste_table` WHERE id = ?
If I create with multiple parameters, it turns like this:
SELECT * FROM `teste_table` WHERE id = ? AND username = ?
So, how can I properly fetch the data from the select. This should be used for multiple purposes, so I could get more than one result, so the best way would be fetch data as array I guess.
I guess I'm close, but can't figure it out. Thanks

Answer 1

I told you to limit your select function to a simple primary key lookup. And now you opened a can of worms. As a result you are getting entangled implementation code and unreadable application code.
$table, $args, $sort, $order, $clause
What all these variables are for? How you're going to call this function - a list of gibberish SQL stubs in a random order instead of plain and simple SQL string? And how to designate a list of columns to select? How to use JOINS? SQL functions? Aliases? Why can't you just write a single SQL statement right away? You already have a function for selects, though without this barbaric error reporting code you added to it:
function prepared_query($mysqli, $sql, $params, $types = ""){
$types = $types ?: str_repeat("s", count($params));
$stmt = $mysqli->prepare($sql)) {
$stmt->bind_param($types, ...$params);
$stmt->execute();
return $stmt;
}
Just stick to it and it will serve you all right.
$sql = "SELECT * FROM `teste_table` WHERE id = ? AND username = ?";
$stmt = prepared_query($mysqli, $sql, [$id, $name]);
$row = $stmt->get_result()->fetch_assoc();
The only specific select function could be, again, a simple primary key lookup:
function crud_find($conn, $table, $id)
{
$table = escape_mysql_identifier($table);
$sql = "SELECT * FROM $table WHERE id=?";
$stmt = prepared_query($conn, $sql, [$id], "i");
return $stmt->get_result()->fetch_assoc();
}
And for the everything else just use a generic function with native SQL.