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PL/SQL中如何传递字符串变量给in

 2008-12-17 13:06:25 来源:WEB开发网   
核心提示:一个简单的存储过程,传递字符串变量作为参数,PL/SQL中如何传递字符串变量给in,传递给过程中的in 子句;但似乎不起作用 , 代码如下 CREATE OR REPLACE PROCEDURE WSREVSECT_5pSectNos varchar2,pRetCode OUT varchar2) ASnCount n

一个简单的存储过程,传递字符串变量作为参数,传递给过程中的in 子句;但似乎不起作用 。 代码如下

CREATE OR REPLACE PROCEDURE WSREVSECT_5
pSectNos varchar2,
pRetCode OUT varchar2
) AS
nCount number;
BEGIN
SELECT count(fksrev) into nCount FROM SREVSECT
WHERE sectno IN (pSectNos ) /* as in 'abc', 'xyz', '012' */;
pRetCode:=to_char(ncount);
End
it works -- the above is the same as
where sectno = pSectNos
though, not what you want. You want it to be:
where sectno in ( 'abc', 'xyz', '012' )
NOT:
where sectno in ( '''abc'', ''xyz'', ''012''' )

当直接使用select count(*) into .. from .. where sectno in (pSectNos) 的时候,相当于where sectno = pSectNos

which is effectively is (else you could never search on a string with commas and
quotes and so on -- it is doing the only logical thing right now).
You can do this:
SQL> create or replace type myTableType as table
of varchar2 (255);
2 /
Type created.
ops$tkyte@dev8i> create or replace
function in_list( p_string in varchar2 ) return myTableType
2 as
3 l_string long default p_string || ',';
4 l_data myTableType := myTableType();
5 n number;
6 begin
7 loop
8 exit when l_string is null;
9 n := instr( l_string, ',' );
10 l_data.extend;
11 l_data(l_data.count) :=
ltrim( rtrim( substr( l_string, 1, n-1 ) ) );
12 l_string := substr( l_string, n+1 );
13 end loop;
14
15 return l_data;
16 end;
17 /
Function created.
ops$tkyte@dev8i> select *
2 from THE
( select cast( in_list('abc, xyz, 012') as
mytableType ) from dual ) a
3 /
COLUMN_VALUE
------------------------
abc
xyz
012
ops$tkyte@dev8i> select * from all_users where username in
2 ( select *
3 from THE ( select cast( in_list('OPS$TKYTE, SYS, SYSTEM')
as mytableType ) from dual ) )
4 /
USERNAME USER_ID CREATED
------------------------------ ---------- ---------
OPS$TKYTE 23761 02-MAY-00
SYS 0 20-APR-99
SYSTEM 5 20-APR-99

使用array如上绑定变量in-list的时候,要注意sql语句的执行计划;因为在有的版本下,cbo无法估计in-list virtual table的行数,产生不正确的执行计划。

Tags:PL SQL 如何

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