【TUNE_ORACLE】檢視每個列的選擇性和基數SQL參考

實驗環境

搭建平臺：VMware Workstation

OS：RHEL 6.10

Grid&DB：Oracle 11.2.0.4

SQL參考

select a.column_name,

       b.num_rows,

       a.num_distinct cardinality,

       round(a.num_distinct / b.num_rows * 100, 2) selectivity,

       a.histogram,

       a.num_buckets

  from dba_tab_col_statistics a, dba_tables b

 where a.owner = b.owner

   and a.table_name = b.table_name

   and a.owner = 'xxx'  --使用者名稱

   and a.table_name = 'xxx';  --表名