Selective Analysis of Oracle Computing Field

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Select a.owner, a.table_name, a.column_name, b.num_rows, a.num_distinct Cardinality, round (a.num_distinct / decode (b.num_rows, 0,1, b.num_rows) * 100,2) selectivity from dba_tab_col_statistics a Dba_tables b where a.owner = b.owner and a.table_name = b.table_name and a.owner = upper ('XXX') and a.table_name = upper (' XXX') and a.column_name = upper ('XXX') -- the closer the column value selectivity is to 100, the better the selectivity, the greater the potential for the column to create an index-- the principle is to view the proportion of non-repetitive records in the corresponding column based on statistical information. This is the end of the content of "selective Analysis of Oracle calculated Fields". Thank you for your reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!