Concat functions in MySQL

Concat functions in MySQL
Usage:
Concat (str1, str2 ,...)

Returns the string generated by the connection parameter. If any parameter is null, the return value is null.

Note:
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)

The Concat function of MySQL can connect one or more strings, such
Mysql> select Concat ('10 ');
+ -------------- +
| Concat ('10') |
+ -------------- +
| 10 |
+ -------------- +
1 row in SET (0.00 Sec)

Mysql> select Concat ('11', '22', '33 ');
+ ------------------------ +
| Concat ('11', '22', '33') |
+ ------------------------ +
| 1, 112233 |
+ ------------------------ +
1 row in SET (0.00 Sec)

When the Concat function of MySQL connects to a string, if one of them is null, null is returned.
Mysql> select Concat ('11', '22', null );
+ ------------------------ +
| Concat ('11', '22', null) |
+ ------------------------ +
| Null |
+ ------------------------ +
1 row in SET (0.00 Sec)

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