Checking for empty fields in mysql table - php

Question

I have a table with 12 columns and 200 rows. I want to efficiently check for fields that are empty/null in this table using php/mysql. eg. "(col 3 row 30) is empty". Is there a function that can do that?
In brief: SELECT * FROM TABLE_PRODUCTS WHERE ANY COLUMN HAS EMPTY FIELDS.

Answer 1

empty != null
select * from table_products where column is null or column='';

Answer 2

SELECT * FROM table WHERE COLUMN IS NULL

Answer 3

As far as I know there's no function to check every column in MySQL, I guess you'll have to loop through the columns something like this...
$columns = array('column1','column2','column3');
foreach($columns as $column){
$where .= "$column = '' AND ";
}
$where = substr($where, 0, -4);
$result = mysql_query("SELECT * FROM table WHERE $where",$database_connection);
//do something with $result;
The = '' will get the empty fields for you.

Answer 4

you could always try this approach:
//do connection stuff beforehand
$tableName = "foo";
$q1 = <<<SQL
SELECT
CONCAT(
"SELECT * FROM $tableName WHERE" ,
GROUP_CONCAT(
'(' ,
'`' ,
column_name,
'`' ,
' is NULL OR ',
'`' ,
column_name ,
'`',
' = ""' , ')'
SEPARATOR ' OR ')
) AS foo
FROM
information_schema.columns
WHERE
table_name = "$tableName"
SQL;
$rows = mysql_query($q1);
if ($rows)
{
$row = mysql_fetch_array($rows);
$q2 = $row[0];
}
$null_blank_rows = mysql_query($q2);
// process the null / blank rows..

Answer 5

<?php
set_time_limit(1000);
$schematable = "schema.table";
$desc = mysql_query('describe '.$schematable) or die(mysql_error());
while ($row = mysql_fetch_array($desc)){
$field = $row['Field'];
$result = mysql_query('select * from '.$schematable.' where `'.$field.'` is not null or `'.$field.'` != ""');
if (mysql_num_rows($result) == 0){
echo $field.' has no data <br/>';
}
}
?>

Answer 6

$sql = "SELECT * FROM TABLE_PRODUCTS";
$res = mysql_query($sql);
$emptyFields = array();
while ($row = mysql_fetch_array($res)) {
foreach($row as $key => $field) {
if(empty($field)) || is_null($field) {
$emptyFields[] = sprintf('Field "%s" on entry "%d" is empty/null', $key, $row['table_primary_key']);
}
}
}
print_r($emptyFields);
Not tested so it might have typos but that's the main idea.
That's if you want to know exactly which column is empty or NULL.
Also it's not a very effective way to do it on a very big table, but should be fast with a 200 row long table. Perhaps there are neater solutions for handling your empty/null fields in your application that don't involve having to explicitly detect them like that but that depends on what you want to do :)

Answer 7

Check this code for empty field
$sql = "SELECT * FROM tablename WHERE condition";
$res = mysql_query($sql);
while ($row = mysql_fetch_assoc($res)) {
foreach($row as $key => $field) {
echo "<br>";
if(empty($row[$key])){
echo $key." : empty field :"."<br>";
}else{
echo $key." =" . $field."<br>"; 1
}
}
}

Answer 8

Here i'm using a table with name words
$show_lang = $db_conx -> query("SHOW COLUMNS FROM words");
while ($col = $show_lang -> fetch_assoc()) {
$field = $col['Field'];
$sel_lan = $db_conx -> query("SELECT * FROM words WHERE $field = '' ");
$word_count = mysqli_num_rows($sel_lan);
echo "the field ".$field." is empty at:";
if ($word_count != 0) {
while($fetch = $sel_lan -> fetch_array()){
echo "<br>id = ".$fetch['id']; //hope you have the field id...
}
}
}

Answer 9

There is no function like that but if other languages are allowed, you can extract the structure of a table and use that to generate the query.
If you only need this for a single table with 30 columns, it would be faster to write the query by hand...