how to get no of days in the current month(count)?

$da = date('d'); // gets the current day of the month
$mth = date('m');    // gets the current month
$yr = date('Y');   // gets the current year
$daysinmonth = cal_days_in_month(CAL_GREGORIAN,$mth,$yr);

echo $daysinmonth;   // this will echo the total no of days in the current month

now you might also want to use the no of days left in the current month from the current day, here's how that's done:-

$baldays = $daysinmonth - $da;

echo $baldays;    // this would echo out the no of days remaining for the current month to end

how to automatically get the first date of the current month in mysql

there are several ways of doing it. here is how i do it. it just feels simpler this way :)


$mth = date('m');                               // gets the current month
$yr = date('Y');                                   // gets the current year

For example, if i want to run a query to get results between the first day of the current month and today, i would write it like this:-

"SELECT * FROM table WHERE date BETWEEN '$yr-$mth-01' AND CURDATE( )"

How to update mysql table ignoring the duplicate fields that are already present

here's how you do it.

INSERT INTO thetable (pageid, name, somefield)
VALUES (1, "foo", "first")
ON DUPLICATE KEY UPDATE (somefield = 'first')

taken from

http://stackoverflow.com/questions/2219786/best-way-to-avoid-duplicate-entry-into-mysql-database

Update one Mysql table with results from another table on a different database

here's how you update one table with results from another database query.


UPDATE
target_database.target_table A                                //database to be updated-target
INNER JOIN source_database.source_table B     //join source database to target
ON B.ProductID = A.ProductID                          //join fields
SET A.Markup = B.Markup                                         //fields to be updated

how to find duplicates in two columns of mysql database table

any one column can have duplicates. but both columns together are unique. this is how you find duplicates

select   columnA,
         columnB,
         count(*)
from     table_name
group by columnA,
         columnB
having   count(*) > 1

how to use the switch statement in php

switch statement can be extremely useful in complex situations.

switch($variable)
{
case "a":
        // run the code if $variable =  a .
break;
case "b":
        // run the code if $variable = b .
break;
case "c":
        // run the code if $variable = c .
break;
default:
        // run the code if $variable is not equal to either a,b or c
}

check existing mysql triggers

SELECT * FROM information_schema.TRIGGERS WHERE TRIGGER_SCHEMA= 'database_name';

OR

SHOW TRIGGERS;

create mysql triggers

table names
testing.name
testing_T.fullname

CREATE TRIGGER addnm AFTER INSERT ON testing
FOR EACH ROW BEGIN
INSERT INTO testing_T SET fullname =  NEW.name;
END;

delimiter |

pull mysql data as options into select field

<?php
$con = mysql_connect("localhost","username","password"); //connection details
$db = mysql_select_db("databasename",$con); // database details
$qry = mysql_query("SELECT somefield FROM sometable WHERE something = 'somevalue' ")or die(mysql_error()); //actual query
echo "<select name=' '>"; 
echo "<option></option>"; //if you want the first one to be blank
while ($row = mysql_fetch_array($qry))
{
$i = $row['somefield'];
echo "<option>$i</option>";
}
echo "</select>";
mysql_close($con);
?>

how to echo mysql retrieved value into a form as default value

// single field that has been retrieved from mysql database
$qry = mysql_query(" SELECT somefield FROM sometable WHERE something =  'some value'  ")or die(mysql_error());
$result = mysql_fetch_row($qry);
<form action="" method="">
<input type="" name="" value=" <?php echo $result[0]; ?>  ">
</form>
// in case of multiple values retrieved from mysql as a simple array

$qry = mysql_query(" SELECT somefield FROM sometable WHERE something =  'some value'  ")or die(mysql_error());

$result = mysql_fetch_array($qry);

<form action="" method="">

<input type="" name="" value=" <?php echo $result[0]; ?> "> //places the first value from mysql

<input type="" name="" value=" <?php echo $result[1]; ?> "> //places the second value

<input type="" name="" value=" <?php echo $result[2]; ?> "> //places the third value

<input type="" name="" value=" <?php echo $result[3]; ?> "> //places the fourth value and so on

</form>

how to use mysql_num_rows example

$qry = mysql_query(" SELECT * FROM abc WHERE something = 'something' ")or die(mysql_error());
$num = mysql_num_rows($qry);
if($num = 0)
{
// run code here
}
    else
    {
    // run code here
    }