MySQL and Oracle database concat () functions

The use parameters of the function are different

MySQL supports multiple string concatenation:

CONCAT (STR1,STR2,...)

Oralce only support two strings of stitching, if you want to stitch multiple strings can be nested use concat

CONCAT (STR1,STR2)

Two, there are null in the parameter processing mode is different

Mysql: Returns the string that results from the connection parameter. If any one of the arguments is NULL, the return value is null.

Oralce: If any one of the arguments is NULL, the returned value is the concatenation of the string.

Third, other aspects

Mysql: If all parameters are non-binary strings, the result is a non-binary string.
If the argument contains any twos binary string, the result is a binary string.

Oracle: If the value connected in Concat is not a string, Oracle attempts to convert it to a string

NOTE: The Oracle stitching string can also use "| |", when the parameter is NULL, the returned value is the concatenation of the string.

MySQL and Oracle database concat () functions