在变量中只取出算术运算符

value is -1 i want to take out - sign in a variable how can i do this

If you want to store the "-" (minus) sign in a separate variable, you need to use the substr() function.

<?php
    echo substr('-1', 0, 1); // will result in "-"
?>

These sql useful to you.

select replace(column_name,'-','') from table_name

Eg:- select replace(-1,'-','')

Thank you.