PostgreSQL游标示例（创建游标，并在函数中遍历之）

--drop function top100cur(refcursor);create function top100cur(refcursor) returns refcursor as $$beginopen $1 for select * from person limit 100;return $1;end$$language plpgsql;----------测试游标----------- SELECT top100cur('abc');-- fetch all from abc;-- drop function from2cur(refcursor,int,int);--这是一个返回游标中在一定范围内记录的函数--create function from2cur(refcursor,int,int)returns setof text as $$declare--声明一些下标变量pnam text;pno text;index int;lower int;upper int;beginindex:=1;lower:=$2;upper:=$3;fetch $1 into pnam,pno;--必须先fetch一条，否则found为falsewhile found loop--只在[lower,upper]区间的记录才返回--if lower<=index and upper>=index thenreturn next pnam||pno;end if;fetch $1 into pnam,pno;index:=index+1;--超过upper后，函数返回--if index>upper then return;end if;end loop;end$$language plpgsql;select top100cur('abc');--创建一个名字为abc的游标-- fetch all in abc;--测试游标select * from from2cur('abc',2,5);