MySQL Error when using an update statement: “you have an error in your SQL syntax...”

Question

I am getting this error from MYSQL server:

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 ''0' = 0, '1' = 0, '2' = 0, '3' = 0, '4' = 0, '5' = 0, '6' = 0, '7' = 0, '8' = 0,' at line 1

And here is the code regarding the update statement:

PreparedStatement getLocations = con.prepareStatement(sql);

ResultSet adjacentSpots = getLocations.executeQuery();

if (adjacentSpots.next()){ 
    int freqAti;
    int total_freq = adjacentSpots.getInt("total_freq");
    newfreqs[0] += total_freq;
    for (int i = 0; i < freqs.length-1; i++) {
        freqAti = adjacentSpots.getInt(""+i);
        newfreqs[i+1] += freqAti;
    }

    sql = "update _frequent_routes set total_freq = " + newfreqs[0];

    for (int i = 1; i < freqs.length; i++) {
        int iAdjusted = i-1; 
        sql += ", '" + iAdjusted + "' = " + newfreqs[i];
    }

    sql += " where device_id= '" + deviceID + "' and intersection1= '" + 
    intersectionName1 + "' and intersection2='" + intersectionName2 + "'"; 

    PreparedStatement updateSpots = con.prepareStatement(sql);

    updateSpots.executeUpdate();
}

An example would be:

update _frequent_routes set total_freq = 2, 0 = 0, 1 = 0, 2 = 0, 3 = 0, 4 = 0, 5 = 0, 6 = 0, 7 = 0, 8 = 0, 9 = 0, 10 = 0, 11 = 0, 12 = 0, 13 = 0, 14 = 0, 15 = 2, 16 = 0, 17 = 0, 18 = 0, 19 = 0, 20 = 0, 21 = 0, 22 = 0, 23 = 0 where device_id= 'some string' and intersection1= 'some string' and intersection2='some string'

I am confident that there is no error in matching the names and types of the columns in the data table. Can anyone spot a syntax error in my update statement?

Answer 1

If your column names are indeed numbers as displayed in your example - then that could be the source of your issue. Mysql column names cannot be solely made up of numbers unless you use backticks (`) to quote them.

From the docs : (See here as well.)

Identifiers may begin with a digit but unless quoted may not consist solely of digits.

So if you just switch your single quotes to backticks on this line sql += ", '" + iAdjusted + "' = " + newfreqs[i]; you should be good to go...

Answer 2

The previous answer says:

From the docs : (See [here][1] as well.)

Identifiers may begin with a digit but unless quoted may not consist solely of digits.

It appears that in fact MYSQL does not allow digit-only identifiers at all in the query. There would be syntax errors as long as I specify those identifiers in my query, whether or not it is quoted. However, if I don't specify the column names, as in a INSERT statement, for example, I could say, "insert into _frequent_routes values (some value, some value, 'some string'...)" and it would write into the database without causing any error.

So one simple solution would be to change the names of those digit-only fields to be non-digit-only. In this case, I could do:

update _frequent_routes set total_freq = 94, slot0 = 4, slot1 = 2, slot2 = 6, slot3 = 2, slot4 = 6, slot5 = 4, slot6 = 6, slot7 = 6, slot8 = 8, slot9 = 2, slot10 = 0, slot11 = 2, slot12 = 0, slot13 = 8, slot14 = 0, slot15 = 4, slot16 = 4, slot17 = 4, slot18 = 2, slot19 = 0, slot20 = 4, slot21 = 4, slot22 = 6, slot23 = 10 where device_id= 'some string' and intersection1= 'some string' and intersection2='some string'

and change the names of the fields correspondingly.