Php array sort() function function sorts an array from the lower value to the higher one, it returns true on success and false on failure.

Php array_merge function used to merges the elements of one or more arrays together to get a new array that contains all arrays elements ordered as arrays passed to function.

The php function abs used to return the absolute value of number passed to function as parameter.

mysql SUBSTRING function keyword split the string for a field into sub strings.

mysql limit keyword optimiztion.. instead of getting all rows in a table you can get a small group of rows that needed to your word!… by this you save server resources.

BIT_LENGTH(str) function Returns the length of the string str in bits.

mysql ASCII function keyword is used to return the numeric value of the leftmost character of the string ’str’. Returns 0 if ’str’ is the empty string and  returns NULL if str is NULL.

CONCAT(str1,str2,…) Returns the string that results from concatenating the arguments to gother. May have one or more arguments.

CHAR_LENGTH(str) function Returns the length of the string str, measured in characters. A multi-byte character counts as a single character.

Sometimes you need to return a limited number of rows such as selecting the first 10 rows of some table, web will show how to do this using MySQL, Sql Server and Oracle