Question

我有第一个查询的结果，然后基于该结果我想与其他表连接，以便我可以选择查询结果和其他表中的字段。

我构建以下

BEGIN
    FOR a_rec in (select col1, min(col2) as col2,col3 from a_tbl group by (col1, col3))
    LOOP
        select a_rec.col2, d_tbl.col4 
        from b_tbl b, c_tbl c, d_tbl d
        where b.col1 = a_rec.col1 and c.col5 = b.col5 and d.col6 = c.col6;
    END LOOP;
END;

然后它提醒我PLS-00428: an INTO clause is expected in this SELECT statement，所以我创建了一个临时表，代码变成了：

BEGIN
    FOR a_rec in (select col1, min(col2) as col2,col3 from a_tbl group by (col1, col3))
    LOOP
        select a_rec.col2, d_tbl.col4 into tmp_tbl
        from b_tbl b, c_tbl c, d_tbl d
        where b.col1 = a_rec.col1 and c.col5 = b.col5 and d.col6 = c.col6;
    END LOOP;
END;

然后我收到类似PLS-00403: expression 'TMP_TBL' cannot be used as an INTO-target of a SELECT/FETCH statement

的错误

也许我应该将第一个查询结果放入临时表中，然后将其与其他表连接起来，尽管我想知道我是否可以在这样的过程中完成它？

Answer 1

如果SELECT INTO语句返回除单行之外的任何内容，则SELECT会引发错误。所以这显然不是你想要的。由于tmp_tbl是一个全局临时表，您可以在循环中执行INSERT SELECT

BEGIN
    FOR a_rec in (select col1, min(col2) as col2,col3 
                   from a_tbl 
                  group by (col1, col3))
    LOOP
      INSERT INTO tmp_tbl( col2, col4 )
        select a_rec.col2, d_tbl.col4 
          from b_tbl b, 
               c_tbl c, 
               d_tbl d
         where b.col1 = a_rec.col1 
           and c.col5 = b.col5 
           and d.col6 = c.col6;
    END LOOP;
END;

但是，由于您说您只是转而在SQL Developer中导出结果数据，因此临时表似乎并不特别有用。您可以删除所有PL / SQL，只需编写一个SELECT语句

    select a.col2, d.col4 
      from (select col1, min(col2) as col2, col3 
               from a_tbl 
              group by col1, col3) a,
           b_tbl b, 
           c_tbl c, 
           d_tbl d
     where b.col1 = a.col1 
       and c.col5 = b.col5 
       and d.col6 = c.col6;

循环基于查询结果获取错误

1 个答案: