Mysql keeps the SQL statement that adds content to the end of the existing content, and mysqlsql

Mysql keeps the SQL statement that adds content to the end of the existing content, and mysqlsql

This command modifies the data table ff_vod and adds 999999999 to the content of the vod_url field.

update ff_vod set vod_url=CONCAT(vod_url,'999999999') where vod_id BETWEEN 1 AND 42553

The following statement only modifies the content where vod_id is 1-53.

where vod_id BETWEEN 1 AND 42553

Analysis of helper's house:

In fact, this mainly uses the CONCAT function, mysql CONCAT () function is used to connect multiple strings into one string.

The following describes the mysql CONCAT () function.

The mysql CONCAT () function is used to connect multiple strings into one character string. It is one of the most important mysql functions. The following describes the mysql CONCAT () function for your reference.

Mysql CONCAT (str1, str2 ,...)
Returns the string generated by the connection parameter. If any parameter is NULL, the return value is NULL. There may be one or more parameters. If all parameters are non-binary strings, the result is a non-binary string. If the independent variable contains any binary string, the result is a binary string. A numeric parameter is converted to an equivalent binary string format. To avoid this, you can use an explicit cast, for example: select concat (CAST (int_col as char ), char_col)

mysql> SELECT CONCAT('My', ‘S', ‘QL');-> ‘MySQL'mysql> SELECT CONCAT('My', NULL, ‘QL');-> NULLmysql> SELECT CONCAT(14.3);-> ‘14.3′

Mysql CONCAT_WS (separator, str1, str2 ,...)
CONCAT_WS () represents CONCAT With Separator, which is a special form of CONCAT. The first parameter is the delimiter of other parameters. The separator is placed between the two strings to be connected. The delimiter can be a string or another parameter. If the Delimiter is NULL, the result is NULL. The function ignores the NULL value after any separator parameter.

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'

Mysql CONCAT_WS () does not ignore any null strings. (However, all NULL values are ignored ).