MySQL LIKE operators & wildcards

问题

I've been reading tutorials and have learned nothing new. I have a table of customers. The customer's first and last names are stored in separate columns. I want to write a query that can search for customers by name, either first, last or BOTH.

Here's what I've got:

$queryyy = "
    SELECT *
    FROM `customers`
    WHERE
        `first_name1` LIKE '".mysql_real_escape_string($_GET['custname'])."%'
        OR `last_name1` LIKE '%".mysql_real_escape_string($_GET['custname'])."'
        AND `status` = 'active'
    LIMIT 6
"; 

If I want to find "Lindsay Thompson", I can query for "lindsay", or for "Thompson" and get the results I want, but if I query for "lindsay thompson" I get nothing.

I feel like I'm missing the point of the wildcards, or not using them properly. Can someone please explain this to me and correct my query..

Thanks

回答1:

Wildcards are introduced to express "any number of any characters" (in case of %).

So

col LIKE '%foo'

will match for foo value and barfoo value.

What you want is actually the opposite - you need to concatenate two columns and check if it's equal to the request, like:

CONCAT(first_name, ' ', last_name) = 'foo bar'

回答2:

a % wildcard will match with any number of characters. To use the example that is shown in the page http://dev.mysql.com/doc/refman/5.0/en/string-comparison-functions.html D%i% would match David.

The problem that you are having is that you are searching either Lindsay or Thompson for %Lindsay Thompson, i.e. search either name for any number of characters followed by the full name. Therefore this will never match.

One option is to run the query on a catenated string of the two names.

SELECT * from customers WHERE CONCAT(first_name1, ' ', last_name1) LIKE '%" .mysql_real_escape_string($_GET['custname']). "%' AND status = 'active' LIMIT 6";

回答3:

Try this, hope it'll help you

 $queryyy = "SELECT * FROM `customers`
             WHERE (`first_name1` LIKE '".mysql_real_escape_string($_GET['custname'])."%' 
             OR `last_name1` LIKE '%".mysql_real_escape_string($_GET['custname'])."') 
             or concat(`first_name1`,' ',last_name1`) 
             LIKE'".mysql_real_escape_string($_GET['custname'])."%' 
             AND `status` = 'active' LIMIT 6"; 

来源：https://stackoverflow.com/questions/15038425/mysql-like-operators-wildcards