In mysql, how does one update the value of a field to its own value and connect it to a string?

In mysql, how to update a field value to its own value connected to a string CONCAT (str1, str2,...) returns the string produced 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 type, 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 'eg: [SQL] UPDATE admin_role SET auth = CONCAT (auth, ',') WHERE id IN (, 4 );