GROUP_CONCAT - concatenate strings in mysql command

In this tutorial, you will learn how to use the MySQL GROUP_CONCAT function to concatenate strings from a group of values with various options.

The following illustrates the GROUP_CONCAT function:

SYNTAX:

GROUP_CONCAT(DISTINCT expression
ORDER BY {column_name | usinged_integer | expression}
SEPARATOR sep);

• You specify the DISTINCT clause to eliminate duplicate values in a group before combining values.
• The ORDER BY clause allows you to sort the values in ascending or descending order before concatenating values. 
• The ORDER BY clause sort the values in ascending ( ASC) order by default. If you want to sort the values in the descending order, you need to specify the DESC explicitly.
• The SEPARATOR specifies a literal value inserted between values in the group. If you do not specify a separator, the GROUP_CONCAT function use a comma (,) as the default separator.
• The GROUP_CONCAT function ignores NULL values. It returns NULL if there was no matching row found or there were no non-NULL values. The GROUP_CONCAT function returns a binary or non-binary string, which depends on the arguments. The maximum length of the return string is 1024 by default. You can extend the returned value’s length by setting the group_concat_max_len system variable at SESSION or GLOBAL level.

Example : 

To get all countries where customers locate as a comma-separated string, you use the GROUP_CONCAT function as follows:

SELECT GROUP_CONCAT(DISTINCT country ORDER BY country)FROM customers;

Result :

                             

However, some customers locate in the same country. To remove the duplicate country’s names, you add the DISTINCT clause as the following query:

SELECT GROUP_CONCAT(DISTINCT country) FROM customers;

Result : 

                         

It is more readable if the country’s names are in ascending order. To sort the country’s name before concatenating, you use the ORDER BY clause as follows:

SELECT GROUP_CONCAT(DISTINCT country ORDER BY country) FROM customers;

Result :

                         

To change the default separator of the returned string from a comma (,) to a semi-colon (;), you use the SEPARATOR clause as the following query:

SELECT GROUP_CONCAT(DISTINCT country ORDER BY country SEPARATOR ';') FROM customers;

Result :

                           

jquery show hide by using jquery toggle method

The toggle() method is used to toggle between show and hide selected HTML elements. If elements are hidden then toggle method will show hidden selected elements and vice versa.

 Syntax:

$(selector).toggle(speed,callback)

Where

Selector = can be an element like div, p, etc.
Speed = Optional parameter that specifies the hide speed with possible values of

1. “slow”
2. “fast”
3. Or value in milliseconds

Callback = after togle () method is completed, an optional callback function to perform certain action can be given.

Example:

 
 
 
    
    

  
    
   
 
     This is Yellow line!!