PHP Functions

1) abs

        Return the absolute value of different numbers:
Example:

       echo abs(-4)."<br>";
       echo abs(-5.3)."<br>";
       echo abs(2)."<br>";
Output:

    4
    5.3
    2

2) arsort

       Sort an array in reverse order and maintain index association
Example: 

       $name=array('c'=>"cat",'a'=>"apple",'b'=>"ball");
       arsort($name);
       foreach ($name as $k=>$v)
      {
         echo "$k=>$v<br>";
      }
Output: 

       c=>cat
       b=>ball
       a=>apple
 
3) asort

   Sort an array and maintain index association
Example:

 $name=array('c'=>"cat",'a'=>"apple",'b'=>"ball");
asort($name);
foreach ($name as $k=>$v)
{

echo "$k=>$v<br>";
}
Output:

a=>apple
b=>ball
c=>cat

4) ceil

Round numbers up to the nearest integer

Example:
echo ceil(4.3)."<br>";
echo ceil(4.5)."<br>";
echo ceil(4.7)."<br>";


echo ceil(-4.3)."<br>";
echo ceil(-4.5)."<br>";
echo ceil(-4.7)."<br>";
Output:
 5
 5
 5
-4
-4
-4

Php MySql Join Query

• INNER JOIN: Returns all rows when there is at least one match in BOTH tables
• LEFT JOIN: Return all rows from the left table, and the matched rows from the right table
• RIGHT JOIN: Return all rows from the right table, and the matched rows from the left table
• FULL JOIN: Return all rows when there is a match in ONE of the tables

SQL INNER JOIN Keyword

The INNER JOIN keyword selects all rows from both tables as long as there is a match between the columns in both tables.

SQL INNER JOIN Syntax

SELECT column_name(s)
FROM table1
INNER JOIN table2
ON table1.column_name=table2.column_name;

SQL LEFT JOIN Keyword

The LEFT JOIN keyword returns all rows from the left table (table1), with the matching rows in the right table (table2). The result is NULL in the right side when there is no match.

SQL LEFT JOIN Syntax

SELECT column_name(s)
FROM table1
LEFT JOIN table2
ON table1.column_name=table2.column_name;

SQL RIGHT JOIN Keyword

The RIGHT JOIN keyword returns all rows from the right table (table2), with the matching rows in the left table (table1). The result is NULL in the left side when there is no match.

SQL RIGHT JOIN Syntax

SELECT column_name(s)
FROM table1
RIGHT JOIN table2
ON table1.column_name=table2.column_name;

SQL FULL OUTER JOIN Keyword

The FULL OUTER JOIN keyword returns all rows from the left table (table1) and from the right table (table2).

The FULL OUTER JOIN keyword combines the result of both LEFT and RIGHT joins.

SQL FULL OUTER JOIN Syntax

SELECT column_name(s)
FROM table1
FULL OUTER JOIN table2
ON table1.column_name=table2.column_name;