I want to get last id in table. First I did this:
String selectId = "SELECT MAX(id) FROM book_store.cart" ;
PreparedStatement ps = conn.prepareStatement(selectId);
rs = ps.executeQuery();
while(rs.next()){
autoIncKey = rs.getInt("id");
}
Here I get error "column id not not found".
Then I changed the query to this, which is working:
String selectId = "SELECT id FROM book_store.cart ORDER BY id DESC LIMIT 1";
I am wondering why the first query is giving me an error and second does not if they are returning the same value?
The first query will return a row with a column name of MAX(id).
Not the most useful name for a column, so change the query to set an alias for that column like this
SELECT MAX(id) id FROM book_store.cart
And now the column will be called id and the rs.getInt("id") will work