引查询常用相关语句-1

1.当前用户下,哪些表的索引个数字超过5个的

select table_name, count(*) cnt from user_indexes

group by table_name having count(*) >= 5 order by cnt desc ;

2.外键未建索引的

select table_name,

constraint_name,

cname1 || nvl2(cname2, ',' || cname2, null) ||

nvl2(cname3, ',' || cname3, null) ||

nvl2(cname4, ',' || cname4, null) ||

nvl2(cname5, ',' || cname5, null) ||

nvl2(cname6, ',' || cname6, null) ||

nvl2(cname7, ',' || cname7, null) ||

nvl2(cname8, ',' || cname8, null) columns

from (select b.table_name,

b.constraint_name,

max(decode(position, 1, column_name, null)) cname1,

max(decode(position, 2, column_name, null)) cname2,

max(decode(position, 3, column_name, null)) cname3,

max(decode(position, 4, column_name, null)) cname4,

max(decode(position, 5, column_name, null)) cname5,

max(decode(position, 6, column_name, null)) cname6,

max(decode(position, 7, column_name, null)) cname7,

max(decode(position, 8, column_name, null)) cname8,

count(*) col_cnt

from (select substr(table_name, 1, 30) table_name,

substr(constraint_name, 1, 30) constraint_name,

substr(column_name, 1, 30) column_name,

position

from user_cons_columns) a,

user_constraints b

where a.constraint_name = b.constraint_name

and b.constraint_type = 'R'

group by b.table_name, b.constraint_name) cons

where col_cnt > ALL

(select count(*)

from user_ind_columns i

where i.table_name = cons.table_name

and i.column_name in (cname1, cname2, cname3, cname4, cname5,

cname6, cname7, cname8)

and i.column_position <= cons.col_cnt

group by i.index_name);

3.当前用户下，哪些组合索引组合列超过4个的

select table_name, index_name, count(*) from user_ind_columns

group by table_name, index_name having count(*) >= 4

order by count(*) desc;

4.针对普通表（大于2GB的表未建任何索引）

select segment_name, bytes/1024/1024/1024 "GB", blocks, tablespace_name

from user_segments where segment_type = 'TABLE'

and segment_name not in (select table_name from user_indexes)

and bytes / 1024 / 1024 / 1024 >= 2

order by GB desc;

5.针对分区表（大于2GB的分区表未建任何索引）

select segment_name, sum(bytes)/1024/1024/1024 "GB", sum(blocks)

from user_segments where segment_type = 'TABLE PARTITION'

and segment_name not in (select table_name from user_indexes)

group by segment_name

having sum(bytes)/1024/1024/1024>=2 order by GB desc;