Question

我使用select case根据条件返回一个值，但是在某些情况下，子查询select会返回多于一行的内容，所以会出现错误。

目标是让函数根据特定条件返回0或1。

SELECT CASE WHEN my_count <= 1 AND stat = "START" THEN 0
            WHEN my_count > 1 AND stat IN ("START", "RUN", "ERR") THEN 1
            ELSE -1
       END AS
INTO return_val
FROM (select
     (SELECT count(DISTINCT(stat) FROM my_table
     WHERE my_table.HIVE = "hive1"
     AND EXTRACT(MONTH FROM PARTITION_DATE) = EXTRACT(MONTH FROM TO_DATE("20190605", 'YYYY-MM-DD'))
       AND EXTRACT(YEAR FROM PARTITION_DATE) = EXTRACT(YEAR FROM TO_DATE("20190605", 'YYYY-MM-DD'))
   ) status_count,
     (SELECT DISTINCT(status) AS status_ FROM my_table
     WHERE EL_F_BDP_PROC_REALTIME.HIVE = "hive1"
     AND EXTRACT(MONTH FROM PARTITION_DATE) = EXTRACT(MONTH FROM TO_DATE("20190605", 'YYYY-MM-DD'))
       AND EXTRACT(YEAR FROM PARTITION_DATE) = EXTRACT(YEAR FROM TO_DATE("20190605", 'YYYY-MM-DD'))
   )status_
     FROM dual
       )x    ;
      RETURN(return_val);
END;

Answer 1

您在声明中有一些地位：

(SELECT DISTINCT(status) AS status_ FROM my_table 
          WHERE EL_F_BDP_PROC_REALTIME.HIVE = 'hive1' 
          AND EXTRACT(MONTH FROM PARTITION_DATE) = EXTRACT(MONTH FROM TO_DATE('20191212', 'YYYY-MM-DD'))
          AND EXTRACT(YEAR FROM PARTITION_DATE) = EXTRACT(YEAR FROM TO_DATE('20191212', 'YYYY-MM-DD'))
        )

并且返回了多一行。

要执行严格，您需要返回一个值示例：

max((SELECT DISTINCT(status) AS status_ FROM my_table 
              WHERE EL_F_BDP_PROC_REALTIME.HIVE = 'hive1' 
              AND EXTRACT(MONTH FROM PARTITION_DATE) = EXTRACT(MONTH FROM TO_DATE('20191212', 'YYYY-MM-DD'))
              AND EXTRACT(YEAR FROM PARTITION_DATE) = EXTRACT(YEAR FROM TO_DATE('20191212', 'YYYY-MM-DD'))
            ))

它正在执行，但是，逻辑可能是错误的

尝试一下：

with tbl as (
select 'START' status,     'hive1' str, to_date('2019-12-11', 'yyyy-mm-dd') dt from dual 
union all
select 'NA' status,     'hive1' str, to_date('2019-12-11', 'yyyy-mm-dd') from dual 
union all
select 'END' status,     'hive1' str, to_date('2019-12-11', 'yyyy-mm-dd') from dual)
select dt, str, listagg(status, ' ') WITHIN GROUP (ORDER BY str) 
from tbl
GROUP BY dt, str

Answer 2

首先，您的查询有几个语法问题。您需要：

将双引号更改为单引号
修复日期格式（20190605与YYYY-MM-DD不兼容）
count(DISTINCT(stat)之后有一个括号缺失
如果在case when .. then之后是as，则该as 应该跟一个（有效的）别名
我假设my_count在 status_count表达式
别名case..when是多余的，并且没有道理

因此，请考虑以下SELECT语句：

status_

您与返回多行相关的问题可能是由于部分DISTINCT(status) AS status_导致的，您可以在其中使用SELECT CASE WHEN status_count <= 1 AND status_ = 'START' THEN 0 WHEN status_count > 1 AND status_ IN ('START', 'RUN', 'ERR') THEN 1 ELSE -1 END INTO :return_val FROM (SELECT (SELECT COUNT(DISTINCT stat) FROM my_table WHERE my_table.HIVE = 'hive1' AND EXTRACT(MONTH FROM PARTITION_DATE) = EXTRACT(MONTH FROM DATE'2019-06-05') AND EXTRACT(YEAR FROM PARTITION_DATE) = EXTRACT(YEAR FROM DATE'2019-06-05')) status_count, (SELECT MAX(DISTINCT status) FROM my_table WHERE EL_F_BDP_PROC_REALTIME.HIVE = 'hive1' AND EXTRACT(MONTH FROM PARTITION_DATE) = EXTRACT(MONTH FROM DATE'2019-06-05') AND EXTRACT(YEAR FROM PARTITION_DATE) = EXTRACT(YEAR FROM DATE'2019-06-05')) status_ FROM dual);或DISTINCT(status) AS status_之类的聚合来在该子查询中精确返回一行，通过转换为MIN

带子查询的select案例在select中返回多行

2 个答案: