phpmyadmin mysql语法错误-多处条件

Question

I need help with my query syntax. I am using phpmyadmin 4 and mysql (not sure of version but suspect it is 5.6. My database has a table called places that contains columns id, city, state, sightings and date . My website takes input from the user via $_POST["city"] and $_POST["state"] . I want to increment sightings by 1 where the table entries for city and state match.

Using phpmyadmin's SQL query builder, I tested possible query structures using place names rather than variables. The following query was successful:

UPDATE places SET sightings = sightings +1 WHERE city =  "Denver" AND state =  "Colorado"

I then clicked "create PHP code" which produced the following:

"UPDATE places SET sightings=sightings+1 WHERE city = \"Denver\" AND state = \"Colorado\"";

I inserted this code, substituting the place names for variables declared from $_POST["city"] and $_POST["state"] ...

$result = cs50::query("UPDATE places SET sightings=sightings+1 WHERE city = \"{$city}\" AND state = \"{$state}\"");

and got error message:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''Denver', 'Colorado')'

I have tinkered with this line of code for hours and can't get it to work. The fact it works in phpmyadmin means its doable, I am just coding it wrong.

The function query is defined in a custom library provided by the course I am studying, CS50. I wonder whether there is some limitation to the function (can post the code if interested) or am I just using the wrong syntax???

Any help is welcome, apologies if my question is confusing, this is relatively new to me.

Answer 1

Have you tried:

"UPDATE places SET sightings=sightings+1 WHERE city = 'Denver' AND state = 'Colorado'";

I've always found that single quotes are more correct than double quotes, even if they are escaped.