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作者:赛迪网 韩劲草 来源:天新网 2008年3月20日
关键字: 数据库 SQL SQL Server Mssql
Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
4628 consistent gets
701 physical reads
0 redo size
1480 bytes sent via SQL*Net to client
514 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
2 sorts (memory)
0 sorts (disk)
28 rows processed
SQL> select code 代码 , substrb(' ',1,item_level*2-2)||b.reg_type 登记注册类型, cnt 家数 from
2 (
3 select
4 case when code3 is not null then code3
5 when code2<>'0' then code2
6 else code1
7 end code,cnt
8 from (
9 select substr(z01_08,1,1)||'00' code1 , substr(z01_08,1,2)||'0' code2 , substr(z01_08,1,3) code3 ,sum(cnt) cnt
10 from (select substr(z01_08,1,3) z01_08,count(*) cnt from cj601 group by substr(z01_08,1,3))
11 group by rollup(substr(z01_08,1,1),substr(z01_08,1,2),substr(z01_08,1,3))
12 ) where code2<>code3 or code3 is null and code1<>'00'
13 )
14 c, djzclx b where c.code=b.reg_code
15 order by 1
16 ;
已选择28行。
已用时间: 00: 00: 00.06
Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=CHOOSE
1 0 SORT (ORDER BY)
2 1 NESTED LOOPS
3 2 VIEW
4 3 FILTER
5 4 SORT (GROUP BY ROLLUP)
6 5 VIEW
7 6 SORT (GROUP BY)
8 7 TABLE ACCESS (FULL) OF 'CJ601'
9 2 TABLE ACCESS (BY INDEX ROWID) OF 'DJZCLX'
10 9 INDEX (UNIQUE SCAN) OF 'SYS_C002814' (UNIQUE)
Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
4628 consistent gets
705 physical reads
0 redo size
1480 bytes sent via SQL*Net to client
514 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
3 sorts (memory)
0 sorts (disk)
28 rows processed
SQL>
大家可以发现,第3种的一致性取和物理读都超过第2种,不过还是快一些。
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