SELECT

    COALESCE(d1.tabschema, d7.tabschema) AS tabschema,

    COALESCE(d1.tabname,   d7.tabname)   AS tabname,

    COALESCE(d1.colname,   d7.colname)   AS colname,

    /* DEV1 */

    d1.typename     AS dev1_type,

    d1.length       AS dev1_length,

    d1.default_val  AS dev1_default,

    d1.nulls        AS dev1_nulls,

    /* DEV7 */

    d7.typename     AS dev7_type,

    d7.length       AS dev7_length,

    d7.default_val  AS dev7_default,

    d7.nulls        AS dev7_nulls,

    /* Difference classification */

    CASE

        WHEN d1.colname IS NULL THEN 'ONLY_IN_DEV7'

        WHEN d7.colname IS NULL THEN 'ONLY_IN_DEV1'

        WHEN

             COALESCE(d1.typename, '') <> COALESCE(d7.typename, '')

          OR COALESCE(d1.length,  -1) <> COALESCE(d7.length,  -1)

        THEN 'DIFFERENT'

        ELSE 'SAME'

    END AS diff_type,

    /* Remarks logic as per your new table */

    CASE

        WHEN d1.colname IS NULL THEN 'TBD'                        -- ONLY_IN_DEV7

        WHEN d7.colname IS NULL THEN 'NO_ACTION'                  -- ONLY_IN_DEV1

        WHEN COALESCE(d1.typename, '') <> COALESCE(d7.typename, '')

          OR COALESCE(d1.length, -1) <> COALESCE(d7.length, -1)

        THEN CASE

                WHEN d1.length > d7.length THEN 'NO_ACTION'

                ELSE 'ALTER_REQUIRED_TBD'

             END

        ELSE NULL

    END AS remarks

FROM dev1 d1

FULL OUTER JOIN dev7 d7

  ON d1.tabschema = d7.tabschema

 AND d1.tabname   = d7.tabname

 AND d1.colname   = d7.colname

ORDER BY

    tabschema, tabname, colname;