WITH dt_e AS (
    SELECT 
        ss.ssa_code,
        ss.ssa_name,
        o.site_id, 
        vendor, 
        bts_tech, 
        bts_down_ts,
        SUM(down_time)
    FROM a_bts_down_old o
    LEFT JOIN b_site si
        ON o.site_id = si.site_id
    LEFT JOIN b_ssa ss
        ON si.ssa_code = ss.ssa_code
    WHERE vendor = 'E'
        AND alarm_element = 'S'
        AND alarm_type = 'S'
        AND bts_down_ts >= '2017-09-12'
        AND bts_up_ts <= '2017-09-13'
    GROUP BY 
        ssa_code,
        ssa_name,
        site_id, 
        vendor, 
        bts_tech, 
        bts_down_ts 
    HAVING COUNT(*) >= 2
),
dt_n AS (
    SELECT 
        ss.ssa_code,
        ss.ssa_name,
        o.site_id, 
        vendor, 
        bts_tech, 
        bts_down_ts,
        SUM(down_time)
    FROM a_bts_down_old o
    LEFT JOIN b_site si
        ON o.site_id = si.site_id
    LEFT JOIN b_ssa ss
        ON si.ssa_code = ss.ssa_code
    WHERE vendor = 'N'
        AND alarm_element = 'B'
        AND alarm_type = 'S'
        AND bts_down_ts >= '2017-09-12'
        AND bts_up_ts <= '2017-09-13'
    GROUP BY 
        ssa_code,
        ssa_name,
        site_id, 
        vendor, 
        bts_tech, 
        bts_down_ts 
) 
SELECT * FROM dt_e 
UNION ALL 
SELECT * FROM dt_n;