Fatal error: Call to a member function bind_param() on a non-object in. Fatal error: Call to a member function bind_param() on a non-object in
1. Error code: $STMT =$this-> mysqli-> prepare($query); // Preprocessed statements
2. Check the code, there is a place that could go wrong: $query, find the SQL statement
$query = “update product set name =?,price=?,description=?where productId=?” ;
Take a closer look at the statement, oh, suddenly, ok?There is no space between where, smart you see it?
Solution: SQL statement error, view SQL statement. Keywords, table names, column names…

Reproduced in: https://www.cnblogs.com/Theladyflower/p/3245893.html