What is the difference between $variable and %$variable%?

I have this piece of code here:

$query = mysql开发者_Go百科_query("SELECT * FROM example WHERE text LIKE '%$value%'");

Would it make a difference if I would use:

$query = mysql_query("SELECT * FROM example WHERE text LIKE '$value'");

If yes, what would it be? What would be the difference?

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Its not a difference in PHP, its a wildcard in SQL. You can read more about it here. Essentially, %

Matches any number of characters, even zero characters

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Yes this has nothing to do with php, its a sql thing, % means like a wildcard there could be 0 or more characters instead of it.

%abc% matches abc, aabca, aabc, abcd
%abc matches dabc, abc but not abcd or tabcd
abc% matches abcd, abc but not dabc, tabcd

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The difference is that '%$value%' will seach for matches containing $value (for exemple if $value = 'foo' it could return 'foobar' or 'barfoobar'), '$value' only matches the exact value of $value.

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In PHP there is no difference (although you might want to take a look at using PDO for your database queries), the '%' symbols affect the query executed in MySQL.

% acts as a wildcard so the first result will return anything that contains the term 'value' in its text attribute, whereas the second will return only records that match exactly the term 'value'