ORA01795: maximum number of expressions in a list is 1000

Load Test的时候发现这么如下这个错误....
 

ORA-01795: maximum number of expressions in a list is 1000

导致这个问题的原因是因为SQL语句中用到了IN字句，结果IN中的元素个数超过了1000导致了这个错误。如下所示...

declare 
    l_cnt pls_integer;
    l_list varchar2(32767);
begin
    select listagg(level, ',') WITHIN group(order by level)
    into l_list
    from dual connect by level<=1000;
    
    execute immediate 'select count(*) from user_objects where object_id in (' || l_list || ')'
    into l_cnt;
end;
/

这个例子中in中元素个数是1000， 可以正常运行，但是下面这个例子就会报错，因为IN中的元素个数超过了1000...

declare 
    l_cnt pls_integer;
    l_list varchar2(32767);
begin
    select listagg(level, ',') WITHIN group(order by level)
    into l_list
    from dual connect by level<=1001;
    
    execute immediate 'select count(*) from user_objects where object_id in (' || l_list || ')'
    into l_cnt;
end;
/

解决这个问题的方法是在程序中将一个IN改成多个IN, 或者把IN List 改成一个SELECT语句，把IN List中的元素放到一个Nested Table中。