[英]Using case inside where clause
I´m trying to create a procedure that has a parameter called m_reaplicacao. 我正在尝试创建一个具有名为m_reaplicacao的参数的过程。 This parameter receives the values 'S' for Yes, 'N' for No and 'T' for all records.
此参数接收值“S”表示“是”,“N”表示“否”,“T”表示所有记录。 When the parameter is Yes, I should return the records with value equals to 9. When the parameter is No, I should return the records different of 9. And finally, when the the value is All, I should return all records from the table.
当参数为Yes时,我应该返回值等于9的记录。当参数为No时,我应该返回不同的9的记录。最后,当值为All时,我应该返回表中的所有记录。 With the code bellow, Oracle says: Compilation errors for PROCEDURE MYDB.CONTAS_A_PAGAR_SPS Error: PL/SQL: ORA-00905: missing keyword Line: 84 Text: ta.id_1a_cbr = 9;
使用下面的代码,Oracle说:PROCEDURE的编译错误MYDB.CONTAS_A_PAGAR_SPS错误:PL / SQL:ORA-00905:缺少关键字行:84文本:ta.id_1a_cbr = 9;
select * from proposta ta
where
ta.estado = 'RJ'
and case
when m_reaplicacao = 'S' then
ta.id_1a_cbr = 9;
when m_reaplicacao = 'N' then
ta.id_1a_cbr <> 9
else null
end case;
I saw a lot of posts, but I did not solve this one. 我看了很多帖子,但我没有解决这个问题。 Can someone help me, please?
有人能帮助我吗?
Don't use a CASE
statement in a WHERE
clause when you really want a simple combination of boolean evaluations. 当您真正想要一个布尔评估的简单组合时,不要在
WHERE
子句中使用CASE
语句。
WHERE ta.estado = 'RJ'
AND ( m_reaplicacao = 'T'
OR (m_reaplicacao = 'S' AND ta.id_1a_cbr = 9)
OR (m_reaplicacao = 'N' AND ta.id_1a_cbr <> 9)
)
If for some reason you really do want to use a CASE
statement, you'd need the CASE
to return a value that you check in the WHERE
clause. 如果由于某种原因您确实想要使用
CASE
语句,则需要CASE
返回在WHERE
子句中检查的值。 For example 例如
WHERE ta.estado = 'RJ'
AND (CASE WHEN m_reaplicacao = 'S' AND ta.id_1a_cbr = 9
THEN 1
WHEN m_reaplicacao = 'N' AND ta.id_1a_cbr <> 9
THEN 1
WHEN m_reaplicacao = 'T'
THEN 1
ELSE 2
END) = 1
This is not generally the clearest way to express this sort of condition, however. 然而,这通常不是表达这种情况的最明确的方式。
You cannot return expressions in CASE
statements, easiest to add additional WHERE
criteria sets: 您无法在
CASE
语句中返回表达式,最容易添加其他WHERE
条件集:
select *
from proposta ta
where ta.estado = 'RJ'
and (
(m_reaplicacao = 'S' AND ta.id_1a_cbr = 9)
OR (m_reaplicacao = 'N' AND ta.id_1a_cbr <> 9)
)
Not sure what you want to happen in the NULL
situation. 不确定在
NULL
情况下你想要发生什么。
You can use CASE in select statements, like this: 您可以在select语句中使用CASE,如下所示:
with d as (
select 'A' as val from dual
union
select 'B' as val from dual
union
select 'C' as val from dual
)
select *
from d
where
case
when val = 'A' then 1
when val = 'B' then 1
when val = 'Z' then 1
end = 1;
Here we're looking for rows where val in ('A','B','Z'). 在这里,我们正在寻找val('A','B','Z')中的行。 In this example, its another way of writing:
在这个例子中,它的另一种写作方式:
select ... where val in ('A','B','Z');
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