在 Oracle 中，我们限制了 SQL 的 IN 子句中仅支持 1000 个项目。我想知道Oracle中是否还有其他此类限制。
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3 回答
3
此处记录了 11.2 的各种限制：http: //docs.oracle.com/cd/B28359_01/server.111/b28320/limits003.htm
一些基于版本的限制：http ://www.oracle.com/us/products/database/enterprise-edition/comparisons/index.html
于 2013-10-21T12:17:58.937 回答
2
Oracle 10g 的限制：
http://docs.oracle.com/cd/B19306_01/server.102/b14237/limits.htm
逻辑限制： http ://docs.oracle.com/cd/B19306_01/server.102/b14237/limits003.htm
物理限制： http ://docs.oracle.com/cd/B19306_01/server.102/b14237/limits002.htm
于 2013-10-21T12:18:28.940 回答
1
有一个简单的技巧可以绕过这个限制。
我有时在临时查询中使用它。
在 Oracle 11.2g 上测试了 5000 个项目。
这种方法的缺点是解析时间长（在我的系统上 5000 个项目大约需要 5-10 秒）。
WITH list AS (
select 1 as X from dual union all
select 2 from dual union all
select 3 from dual union all
......
......
......
select 4997 from dual union all
select 4998 from dual union all
select 4999 from dual union all
select 5000 from dual
)
SELECT /*+gather_plan_statistics */ * FROM table123
WHERE x IN ( SELECT * FROM list );
select * from table( dbms_xplan.display_cursor (format=>'ALLSTATS LAST'));
----------------------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | OMem | 1Mem | Used-Mem |
----------------------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | | 5000 |00:00:00.24 | 29 | | | |
|* 1 | HASH JOIN RIGHT SEMI| | 1 | 1 | 5000 |00:00:00.24 | 29 | 1066K| 1066K| 1339K (0)|
| 2 | VIEW | VW_NSO_1 | 1 | 5000 | 5000 |00:00:00.24 | 0 | | | |
| 3 | VIEW | | 1 | 5000 | 5000 |00:00:00.21 | 0 | | | |
| 4 | UNION-ALL | | 1 | | 5000 |00:00:00.18 | 0 | | | |
| 5 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | | | |
| 6 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | | | |
| 7 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | | | |
| 8 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | | | |
| 9 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | | | |
..........
..........
..........
|5000 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | | | |
|5001 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | | | |
|5002 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | | | |
|5003 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | | | |
|5004 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | | | |
|5005 | TABLE ACCESS FULL | TABLE123 | 1 | 9999 | 9999 |00:00:00.02 | 29 | | | |
----------------------------------------------------------------------------------------------------------------------
于 2013-10-21T16:11:13.663 回答