Oracle archive data query (partition query)

Oracle archive data query (partition query) the SQL statement used to query 201212 month data records is as follows: SQL code www.2cto.com SELECT COUNT (DISTINCT (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog c WHERE TO_CHAR (c. end_time, 'yyyymmm ') = '000000'. After waiting for two hours, no result is returned... find the database maintenance personnel and give the following SQL statement SQL code SELECT COUNT (DISTINCT (emp_use_count) FROM (SELECT DISTINCT (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121201) c union all select distinct (c. caller_n Br) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121202) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121203) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121204) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121205) c UNION ALL SE Lect distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121206) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121207) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121208) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p _ 20121209) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121210) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121211) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121212) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub _ Calllog_his PARTITION (p_20121213) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121214) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121215) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121216) c union all select distinct (c. caller_nbr) AS emp _ Use_count FROM tab_pub_calllog_his PARTITION (p_20121217) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121218) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121219) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121220) c UNION ALL SELECT DISTI NCT (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121221) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121222) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121223) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121224) C union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121225) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121226) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121227) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_hi S PARTITION (p_20121228) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121229) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121230) c union all select distinct (c. caller_nbr) AS emp_use_count FROM tab_pub_calllog_his PARTITION (p_20121231) c. The result is displayed in less than 6 seconds. It is really strong enough!