MySQL SQL CONCAT string connection

There is a string concatenation function concat () in the MySQL tutorial, so let's talk about how to use it.

Concat syntax
Concat (STR1,STR2,...)

Look at a section of Dedecms search program inside the code

$k = Addslashes ($k);
if ($this->searchtype== "title")
{
$kwsqls [] = "arc.title like '% $k% '";
}
Else
{
$kwsqls [] = "concat (Arc.title, ', Arc.writer, ', arc.keywords) like '% $k% '";
}

From Concat (Arc.title, ', Arc.writer, ', arc.keywords) like '% $k% '; We are inspired, the original kind can also do oh, to query the characters to use the concat link up, and then query Oh.

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