即使where子句匹配，sql也会返回0行

I am trying to execute

  SELECT * FROM `product_laptop` WHERE name = "Acer  Sdfsdf"

MySQL returned an empty result set (i.e. zero rows). (Query took 0.0010 seconds.)

even though there is an entry with the name Acer  Sdfsdf` and name is also defined as unique key.

Maybe you should try like to get the correct data:

SELECT * FROM `product_laptop` WHERE name LIKE "Acer%"

Would that suit your needs?

The = requires an exact match, using like with the % wildcard will give you the results you want. This won't match exact records though and will allow for all sorts of variations.

SELECT * FROM `product_laptop` WHERE name like "Acer%Sdfsdf"

With LIKE you can use the following two wildcard characters in the pattern:

% matches any number of characters, even zero characters.

_ matches exactly one character.

http://dev.mysql.com/doc/refman/5.7/en/string-comparison-functions.html

You can use:

$name = preg_replace('/\s+/', '%', trim($name));

to convert all whitespaces to wildcards.