(转载)REF CURSOR 小结
REF CURSOR 小结 利用REF CURSOR,可以在程序间传递结果集(一个程序里打开游标变量,在另外的程序里处理数据)。也可以利用REF CURSOR实现BULK SQL,提高SQL性能。REF CURSOR分两种,Strong REF CURSOR 和 Weak REF CURSOR。Strong REF CURSOR:指定retrun type,CURSOR变量的类型必须和return type一致。DECLARETYPE strongcurtyp IS REF CURSOR RETURN emp%ROWTYPE;emp_cv strongcurtyp;Weak REF CURSOR:不指定return type,能和任何类型的CURSOR变量匹配。DECLARETYPE weakcurtyp IS REF CURSOR;weak_cv weakcurtyp;any_cv SYS_REFCURS
case
SELECT sum(case t.station_id when '00594' then 1 end) A, sum(case when t.station_id > '00594' then 1 end) B, sum(case when t.station_id < '00594' then '1' end) C FROM db_station t[@more@]