SQL query for displaying teacher attendance - mysql

Question

My teacher table is like:'
I have a teacher attendance table with data like as shown below:-
I'm trying to write codes which when executed will populate an excel file in the format given below. Where A= Absent, P= Present and, S= Sunday.
Logic for Present (P) : For any given date if ta_clock_in_tm & ta_clock_out_tm both are present then it's P.
Logic for Absent (A) : If no records exist for dates of the month in the teacher attendance table then it's A.
I also want to mark Sundays as S and calculate Total Present days and absent days.
I have not done anything like this before. I'm really confused about the sql query. Are both my tables enough to meet my requirement??
function export_to_mwiseallattenexcel($mnth)
{
$columnHeader ='';
$setData='';
$currYr = date("Y");
$noDaysInGvnMonth = cal_days_in_month(CAL_GREGORIAN, $mnth, $currYr);
$columnHeader = "Sl No"."\t"."Emp Name"."\t";
for($i=1; $i<=$noDaysInGvnMonth; $i++)
{
$columnHeader .= $i."\t";
}
$columnHeader .= "Total Working Days"."\t"."Total Absent"."\t"."Total Present"."\t"."Remarks"."\t";
$sql="";//<---WHAT TO WRITE HERE?????
$query = $this->db->query($sql);
if ($query->num_rows() > 0) {
foreach ($query->result_array() as $row) {
$rowData = '';
foreach($row as $value)
{
$value = '"' . $value . '"' . "\t";
$rowData .= $value;
}
$setData .= trim($rowData)."\n";
}
}
header("Content-Encoding: UTF-8");
header("Content-type: application/vnd.ms-excel");
header("Content-Disposition: attachment; filename=Attendance_as.xls");
header("Pragma: no-cache");
header("Expires: 0");
echo ucwords($columnHeader)."\n".$setData."\n";
}
Please help me with the SQL query. Thanks.

Answer 1

Open a connection to your server. There you can query EVERY command you want:
The code is:
try {
$sql = new PDO('mysql: host=localhost:3306; dbname=dbname', 'user', 'pwd');
$sql->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$statement = "do something";
$sql -> query($statement)
} catch(PDOException $e) {
echo 'Connection failed: (f) ' . $e->getMessage();
}
Some interesting commands are:
CREATE TABLE table (any datatypes); -> creates new table
INSERT INTO table () VALUES (value1),(value2); -> fills table with values
ALTER TABLE table CHANGE old_name new_bane datatype; -> change table
ALTER TABLE table DROP COLUMN user_id; -> drops a column from a database
DELETE FROM table WHERE condition; -> delete all values where condition is true
UPDATE table SET data=value WHERE condition; updates values inside a table where condition is true