/*
1. 抓出列選擇性》=20 的列
2. 這個列沒有建立索引
3. 這個列出現在where條件中
*/這裡面的owner值自己改改。(師從落落，請勿噴我
with u as
(select 'normphone' owner from dual)
select a.owner,
a.table_name,
a.column_name,
a.selectivity,
b.owner,
b.table_name,
b.column_name,
c.owner,
c.table_name,
c.column_name
from (select a.owner,
a.table_name,
a.column_name,
b.num_rows,
a.num_distinct cardinality,
decode(b.num_rows,
null,
0,0,
0,round(a.num_distinct / b.num_rows * 100, 2)) selectivity,
a.histogram,
a.num_buckets
from dba_tab_col_statistics a, dba_tables b, u
where a.owner = b.owner
and a.owner = u.owner
and a.table_name = b.table_name) a
left join (select r.name owner,
o.name table_name,
c.name column_name,
equality_preds, ---等值過濾
equijoin_preds, ---等值join過濾 比如where a.id=b.id
nonequijoin_preds, ----不等join過濾
range_preds, ----範圍過濾 &get; &get;= < <= between and
like_preds, ----like過濾
null_preds, ----null 過濾
timestamp
from sys.col_usage$ u, sys.obj$ o, sys.col$ c, sys.user$ r, u
where o.obj# = u.obj#
and c.obj# = u.obj#
and c.col# = u.intcol#
and o.owner# = r.user#
and r.name = u.owner) b
on a.owner = b.owner
and a.table_name = b.table_name
and a.column_name = b.column_name
left join (select t.index_owner owner, t.table_name, t.column_name
from all_ind_columns t, u
where t.index_owner = u.owner) c
on a.owner = c.owner
and a.table_name = c.table_name
and a.column_name = c.column_name
where a.selectivity >= 20
and (b.owner is not null and b.table_name is not null and
b.column_name is not null)
and(c.owner is null and c.table_name is null and c.column_name is null)
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