如何将DEFINE变量设置为PL/SQL中另一个已定义表中的选择

如何使用DEFINE函数设置一个等于另一个SELECT语句结果的变量？结果仅为单列/单行选择

例如：

DEFINE source_table = mysourcetable
DEFINE use_date = select distinct max(txn_date) from &source_table

select asdf1, asdf2
from &source_table s
where &use_date between s.eff_date and s.end_date

我当前遇到的错误是WHERE子句中&usedate变量上的“缺少表达式”

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希望这是有意义的。

刚刚想好了。WHERE子句中的&use\u日期需要放在括号中

DEFINE source_table = mysourcetable
DEFINE use_date = select distinct max(txn_date) from &source_table

select asdf1, asdf2
from &source_table s
where (&use_date) between s.eff_date and s.end_date

或者将定义查询放在括号中：

DEFINE source_table = mysourcetable
DEFINE use_date = (select distinct max(txn_date) from &source_table)

select asdf1, asdf2
from &source_table s
where &use_date between s.eff_date and s.end_date

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为了完整起见，这是使用列的另一种方式。。新值命令：

DEFINE source_table = mysourcetable

column  the_col new_value  use_date 

select distinct max(txn_date) the_col from &source_table;

PROMPT The value is &use_date 

select asdf1, asdf2
from &source_table s
where TO_DATE('&use_date') between s.eff_date and s.end_date;