Count same values in different column mysql - php

Question

I need to count how many times in ripeted the same values in different columns for the same id..
I'll try to clarify with an example:
TABLE:
+-----+-----+-----+-----+-----+
| id | d01 | d02 | d03 | d04 |
+=====+=====+=====+=====+=====+
| 1 | A | A | B | B |
+-----+-----+-----+-----+-----+
| 2 | A | A | A | A |
+-----+-----+-----+-----+-----+
| 3 | B | B | A | A |
+-----+-----+-----+-----+-----+
| 4 | A | A | A | A |
+-----+-----+-----+-----+-----+
| 5 | A | A | A | A |
+-----+-----+-----+-----+-----+
| 6 | B | A | A | A |
+-----+-----+-----+-----+-----+
I need to know how many times the value "B" is repeating for any person (ID)..
Is that possible to do that? RESULTS
+-----+-----+-----+
| id | count B |
+=====+=====+=====+
| 1 | 2 |
+-----+-----+-----+
| 2 | 0 |
+-----+-----+-----+
| 3 | 2 |
+-----+-----+-----+
I was thinking to use the function "SUM" but I have no idea how to display just the single ID.
Thanks in advance, hope the question is clear enough!

Answer 1

If there are only four columns:
SELECT id, (d01 = 'B') + (d02 = 'B') + (d03 = 'B') + (d04 = 'B')
FROM tablename
No there are 31 columns
That's a problem which you can solve in two ways:
Repeat the condition for the other 27 columns :)
Normalize your structure so that each value is dependent on both the id and a numeric value that represents a calendar.
The PHP way
You can also fetch all columns and let PHP solve this for you:
$res = $db->query('SELECT * FROM tablename');
foreach ($res->fetchAll(PDO::FETCH_ASSOC) as $row) {
$id = $row['id'];
unset($row['id']); // don't count the id column
$count = count(array_keys($row, 'B', true));
printf("ID %d: %d\n", $id, $count);
}

Answer 2

Since you seem to be using mysql_*:
// SHOW COLUMNS returns all the columns and constrains of the defined table
// We only need the column names so we will be later calling it by 'Field'
$sql = mysql_query("SHOW COLUMNS FROM table"); //your table name here
$val_to_count = 'B'; //value to count here
$id = 1; //id to search for
$new_sql = 'SELECT id, ';
// In this loop we will construct our SELECT query using the columns returned
// from the above query
while($row=mysql_fetch_array($sql)){
if($row['Field']!='id'){
$new_sql .= ' ('.$row['Field'].' = "'.$val_to_count.'") + ';
}
}
//Removing the last "+ " produced in the select query
$new_sql = rtrim($new_sql,"+ ");
$new_sql .= ' as count FROM table WHERE id = '.$id; //table name here again
// so $new_sql now has an output like:
// SELECT ID, (d01 = 'B') + (d02 = 'B') ... WHERE id = 1
$sql2 = mysql_query($new_sql);
//executing the constructed query with the output below
while($row2=mysql_fetch_array($sql2)){
echo 'ID - '.$row2['id']."<br>";
echo 'Count - '.$row2['count']."<br>";
}
Note:
mysql_* is deprecated, please consider to migrate to mysqli_*