转换为 pl/sql

Question

这是我的 SQL Select 语句，我想将其转换为在 PL/SQL 代码中调用的语句：

SELECT StockID 
  FROM StockPrice 
 WHERE StockType ='Technology' AND Price < 150 
    OR StockType ='Retail' AND Price < 150;

任何想法......

Answer 1

假设查询返回单个值的一个简单选项是

DECLARE
  l_stockid stockprice.stockid%TYPE;
BEGIN
  SELECT stockid
  INTO l_stockid
  FROM stockprice
  WHERE (stocktype = 'Technology' AND price < 150)
     OR (stocktype = 'Retail'     AND price < 150);
END;
/

不过，WHERE 可以重写为

  WHERE price < 150
    AND stocktype in ('Technology', 'Retail')

如果该 select 语句返回多于一行，您将得到 too_many_rows，问题是您想如何处理它？抛出异常？选入收藏？有些不同？这取决于。