Your examples should be using single quotes for strings not double quotes. The latter are for quoting identifiers (eg if you named a table "select") and throug

Your examples should be using single quotes for strings not double quotes. The latter are for quoting identifiers (eg if you named a table "select") and through an accident of SQLite history degrade to a string if no matching identifier is found. + is the SQL numeric addition operator. || is string concatenation. sqlite> select 3 || 3 ; 33 sqlite> select 'a'+'b' ; 0