sql - SQL 用单词 else 替换空的 SQL SELECT 将结果发布到 Oracle

Question

我正在尝试解决以下问题：

我想做一个选择，当结果为空时，它应该被替换为“空”，否则结果的所有行都应该在那里。喜欢：

if (select has no result)
{
 One Line as result with 'no result'
}
else
{
 post every line of the select result
}

那是我的尝试：

select case when count(*) = 0
   then 'no Entry'
   else Members --all Members should be here
END as Member
from tableMember where Membergroup = 'testgroup';

感谢所有可以帮助我的人！

请向我展示在Oracle中使用查询所需的完整代码

Answer 1

甲骨文

DECLARE C INTEGER;
SELECT COUNT(*) INTO C FROM tableMember WHERE Membergroup = 'testgroup';

IF C > 0
THEN
    SELECT * FROM tableMember;
ELSE
    SELECT 'No results!' FROM tableMember;
END IF;

仅限 MS-SQL

IF EXISTS(SELECT * FROM tableMember WHERE Membergroup = 'testgroup')
BEGIN
    SELECT * FROM tableMember
END
ELSE
BEGIN
    SELECT 'No results!'
END

Answer 2

尝试这个：

DECLARE @counter int

SET  @counter = (select count(*) from tableMember where Membergroup = 'testgroup');

IF (@counter > 0)
BEGIN
     SELECT * FROM Members
END
ELSE
BEGIN
     SELECT 'No results!'
END

问候

Answer 3

我宁愿在应用程序代码而不是存储过程中这样做。您在这里尝试做的是与用户体验相关的工作，恕我直言，数据库不应该关心这些工作。