Oracle SQL實現分頁查詢

2021-08-02 08:16:54 字數 4322 閱讀 7300

sql> desc test; 

名稱 是否為空? 型別

--------------------- -------- ---------------

id not null number(8)

username varchar2(32)

password varchar2(32)

age number(3)

birthday date

address

varchar2(40)

sql> select count(*) from test;

count(*)

----------

5000001

sql> select

*from

test

where

rownum

<10;

idusername

password

agebirthday

address--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

325610

user325610

password325610

1015

-10月-15

the_earth

325611

user325611

password325611

1115

-10月-15

the_earth

325612

user325612

password325612

1215

-10月-15

the_earth

325613

user325613

password325613

1315

-10月-15

the_earth

325614

user325614

password325614

1415

-10月-15

the_earth

325615

user325615

password325615

1515

-10月-15

the_earth

325616

user325616

password325616

1615

-10月-15

the_earth

325617

user325617

password325617

1715

-10月-15

the_earth

325618

user325618

password325618

1815

-10月-15

the_earth

這種方式比較好理解,而且內層查詢效率高,整體查詢效率較穩定。

sql> select *

2from (select row_.*, rownum rownum_

3from (select *

4from test

5order

by id asc) row_

6where rownum <= 20)

7where rownum_ >= 10;

或者

sql>  select *

2from (select test.*, rownum rownum_ from test where rownum <= 5000000

order

by id asc)

3where rownum_ >= 4999990;

查詢結果

id

username

password

agebirthday

address--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

---4999989

user4999989

password4999989

6915

-10月-15

the_earth

4999990

user4999990

password4999990

7015

-10月-15

the_earth

4999991

user4999991

password4999991

7115

-10月-15

the_earth

4999992

user4999992

password4999992

7215

-10月-15

the_earth

4999993

user4999993

password4999993

7315

-10月-15

the_earth

4999994

user4999994

password4999994

7415

-10月-15

the_earth

4999995

user4999995

password4999995

7515

-10月-15

the_earth

4999996

user4999996

password4999996

7615

-10月-15

the_earth

4999997

user4999997

password4999997

7715

-10月-15

the_earth

4999998

user4999998

password4999998

7815

-10月-15

the_earth

4999999

user4999999

password4999999

7915

-10月-15

the_earth

已選擇11行。

採用這種方式,查詢越靠後,效率越低,整體需要查詢兩次,而且逐條比較,不推薦使用。

sql>  select *

2from test

3where id not

in4 (select id from test

5where rownum <= 20)

6and rownum <= 10

order

by id asc;

這種是採用minus函式取差集的方式獲取,同樣查詢越靠後,效率越低

sql> select *

2from test

3where rownum <= 20

4 minus

5select * from test where rownum <= 10;

待續……

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