Question

我在游标中有一个简单的查询

Cursor some_cursor IS
    select 
       sum(some_field) 
    from some_table table_1 
    where 
        table_1.TYPE =1                         
        AND TO_CHAR(table_1.date,'YYYYMMDD') = '20090905'
        AND table_1.f2 = 962
        AND table_1.f3 = 41813;

然后我做

   fetch some_cursor into some_var;--some_var is of type Number, cursor is open

当我运行此查询时，some_var有可能为NULL。在这种情况下，id喜欢它取0值;

像

这样的东西

    --C like pseudocode of what I want
   (some_cursor!=Null?(fetch some_cursor into some_var):(some_var:=0))

有办法做到这一点吗？我正在考虑将上述查询重写为

Cursor some_cursor IS
    select 
       sum(some_field),count(*) 
    from some_table table_1 
    where 
        table_1.TYPE =1                         
        AND TO_CHAR(table_1.date,'YYYYMMDD') = '20090905'
        AND table_1.f2 = 962
        AND table_1.f3 = 41813;

然后写

   fetch some_cursor into some_var,some_counter;

   if (some_counter = 0) then
   begin
       some_var :=0;
   end

但这意味着重写10个游标（是的，没有那么多）。也许plsql有一个更清洁的方式。

提前致谢

Answer 1

尝试：

SELECT NVL(SUM(some_field),0)
  from some_table table_1 
 where table_1.TYPE =1                                                 
   AND TO_CHAR(table_1.date,'YYYYMMDD') = '20090905'
   AND table_1.f2 = 962
   AND table_1.f3 = 41813;

Answer 2

当你在那里时，你可能会纠正其他几个问题：

使用隐式游标而不是显式
如果可以避免，请不要将函数应用于表格列。

因此：

Declare
   some_var Number;
Begin
   select Coalesce(sum(some_field),0)
   into   some_var
   from   some_table table_1   
   where  table_1.TYPE =  1                                                   
    AND   table_1.date >= date '2009-09-05' 
    AND   table_1.date <  date '2009-09-06' 
    AND   table_1.f2   =  962  
    AND   table_1.f3   =  41813;
End;

PL SQL - 类似（！a？0：a）功能

2 个答案: