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Old 11-08-2007, 11:00 PM
Gopisoft Gopisoft is offline
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Join Date: Feb 2007
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Default Re: group_concat in MySQL

Hi,

CONCAT() and CONCAT_WS() function

CONCAT() Function

Code:
Syntax
CONCAT(str1,str2,...)
This function eeturns the string that results from concatenating the arguments. May have one or more arguments. If all arguments are non-binary strings, the result is a non-binary string. If the arguments include any binary strings, the result is a binary string. A numeric argument is converted to its equivalent binary string.

CONCAT() returns NULL if any argument is NULL.

Example:

Code:
SELECT CONCAT(CAST(int_col AS CHAR), char_col);

mysql> SELECT CONCAT('My', 'S', 'QL');
        -> 'MySQL'
mysql> SELECT CONCAT('My', NULL, 'QL');        
        -> NULL
mysql> SELECT CONCAT(14.3);
        -> '14.3'
CONCAT_WS() Function

Code:
Syntax
CONCAT_WS(separator,str1,str2,...)
CONCAT_WS() function for Concatenate With Separator and is a special form of CONCAT(). The first argument is the separator for the rest of the arguments. The separator is added between the strings to be concatenated. The separator can be a string, as can the rest of the arguments. If the separator is NULL, the result is NULL.

Note: CONCAT_WS() does not skip empty strings. However, it does skip any NULL values after the separator argument.

Code:
mysql> SELECT CONCAT_WS(',','First name','Second name','Last Name');
        -> 'First name,Second name,Last Name'
mysql> SELECT CONCAT_WS(',','First name',NULL,'Last Name');
        -> 'First name,Last Name'
Thanks
R.Gopi.
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