How to compare an inserted sentence with existing ones in the comic returning the probability of being similar?

Question

I would like to know how to compare a phrase inserted by the user with those in the BD in order to return the probability of being similar. I have a similar code that compares two strings in JAVA but needed to do it in PHP+Mysql

Answer 1

The strcasecmp function compares two strings without case differentiation.

$var1 = 'A';
$var2 = 'a';

//comparacao case insensitive
if(strcasecmp($var1, $var2) == 0) {

    echo $var1.' (igual) '.$var2; //Imprime 'A igual a'
}

The strcmp function compares two strings differentiating uppercase and lowercase.

//comparacao case sensitive
if(strcmp($var1, $var2) != 0) {

    echo $var1.' (diferente) '.$var2; //Imprime 'A diferente de a'
}

$var1 = 'A';
$var2 = 'B';

//comparacao case sensitive
if(strcmp($var1, $var2) != 0) {

    echo $var1.' (diferente) '.$var2; //Imprime 'A diferente de B
}

Answer 2

There is the function similar_text(), it calculates the similarity between two strings, for example:

similar_text('Olá mundo', 'Oi Mundo', $percentualSimilaridade);
echo 'Percentual de similaridade: ' . $percentualSimilaridade; // Imprime 66.6666666667

That is, the two sentences have approximately 66.67% similarity.