Oracle Like 运算符在 Where 条件和解码

Question

我正在尝试对来自多个 table 的 return 记录编写一个 PL-SQL 查询，并使用解码来允许空值比较，

PROCEDURE GetResults(FromDate DATE,pToDate DATE, DeptName VARCHAR2 DEFAULT NULL,p_ref  OUT SYS_REFCURSOR ) IS
BEGIN
OPEN p_ref FOR
SELECT e.First_Name,e.LastName,e.Department
FROM
Employee e, Department d
Where  e.JoiningDate >=FromDate
      AND e.JoiningDate <=ToDate
     AND  NVL(e.Department,'~') = decode(DeptName,null,NVL(e.Department,'~'),DeptName
End GetResults

结果是 return 仅在 DeptName 与数据库值完全匹配的情况下，但我想要查询 return 一些东西 e.Department like '%DeptName%'

Answer 1

除了布尔逻辑之外不需要任何东西：

WHERE e.JoiningDate >= FromDate AND
      e.JoiningDate <= ToDate AND
      (DeptName IS NULL OR e.Department = DeptName)

如果您希望 NULL 参数仅匹配 NULL 值，请使用：

WHERE e.JoiningDate >= FromDate AND
      e.JoiningDate <= ToDate AND
      (DeptName IS NULL AND e.Department IS NULL OR 
       e.Department = DeptName
      )

我还建议您为参数命名，这些名称更明显是参数。我经常使用 in_ 或 out_:

作为前缀

PROCEDURE GetResults (
    in_FromDate DATE,
    in_ToDate DATE,
    in_DeptName VARCHAR2 DEFAULT NULL,
    out_p_ref  OUT SYS_REFCURSOR
) IS

Oracle Like 运算符在 Where 条件和解码

Oracle Like Operator in Where condition and decode

java

sql

oracle

plsql

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