concat
Description
Syntax
‘VARCHAR concat (VARCHAR,…)’
Connect multiple strings and return NULL if any of the parameters is NULL
example
mysql> select concat("a", "b");+------------------+*124concat ('a','b') 1244;+------------------+1.2.2.2.2.2.+------------------+mysql> select concat("a", "b", "c");+-----------------------+124concat ('a','b','c') 1244;+-----------------------+1.2.2.2.2.2.2.+-----------------------+mysql > select concat ("a", null, "c");+------------------------+124concat (a), NULL,'c')+------------------------+No. No. No.+------------------------+