将重复声明分配给变量
问题描述:
以下是工作存储过程。如何将case语句下的重复代码分配给一个变量并使用它,以便减少编码行的数量?该过程的目的是使用每个CASE语句的start_date和end_date更新表。感谢您的帮助和建议。将重复声明分配给变量
BEGIN
UPDATE period x
SET start_date = CASE
when return_period = 'L3M' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -2 Month))
when return_period = 'YTD' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL 1-MONTH((select max(monthend_date) from returns y
WHERE x.account_id=y.account_id)) Month))
when return_period = '1YR_CUM' or return_period = '1YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -11 Month))
when return_period = '2YR_CUM' or return_period = '2YR_ANN' then
last_day(date_add((select max(monthend_date) from eturns y WHERE x.account_id=y.account_id),INTERVAL -23 Month))
when return_period = '3YR_CUM' or return_period = '3YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -35 Month))
when return_period = '4YR_CUM' or return_period = '4YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -47 Month))
when return_period = '5YR_CUM' or return_period = '5YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -59 Month))
when return_period = '6YR_CUM' or return_period = '6YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -71 Month))
when return_period = '7YR_CUM' or return_period = '7YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -83 Month))
when return_period = '8YR_CUM' or return_period = '8YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -95 Month))
when return_period = '9YR_CUM' or return_period = '9YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -107 Month))
when return_period = '10YR_CUM' or return_period = '10YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -119 Month))
when return_period = '11YR_CUM' or return_period = '11YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -131 Month))
when return_period = '12YR_CUM' or return_period = '12YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -143 Month))
when return_period = '13YR_CUM' or return_period = '13YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -155 Month))
when return_period = '14YR_CUM' or return_period = '14YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -167 Month))
when return_period = '15YR_CUM' or return_period = '15YR_ANN' then
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL -179 Month))
when return_period = 'SI_CUM' or return_period = 'SI_ANN' then
(select min(monthend_date) from returns y WHERE x.account_id=y.account_id)
END
,
end_date=(select max(monthend_date) from returns y WHERE x.account_id=y.account_id)
;
END
答
这是您的重复表达:
last_day(date_add((select max(monthend_date) from returns y WHERE x.account_id=y.account_id),INTERVAL {months} MONTH))
唯一的区别是在{months}
值。 首先,我会写的表达有点短:
last_day((select max(monthend_date) from returns y WHERE x.account_id=y.account_id) + INTERVAL {months} MONTH)
然后我会使用情况下,只有在{month}
部分:
UPDATE period x
SET start_date = last_day((select max(monthend_date) from returns y WHERE x.account_id=y.account_id) + INTERVAL
CASE
when return_period = 'L3M' then -2
when return_period = 'YTD' then -1
when return_period = '1YR_CUM' or return_period = '1YR_ANN' then -11
when return_period = '2YR_CUM' or return_period = '2YR_ANN' then -23
when return_period = '3YR_CUM' or return_period = '3YR_ANN' then -35
when return_period = '4YR_CUM' or return_period = '4YR_ANN' then -47
# [...]
END
MONTH),
end_date=(select max(monthend_date) from returns y WHERE x.account_id=y.account_id);
你也可以写这样说:
UPDATE period x
SET start_date = last_day((select max(monthend_date) from returns y WHERE x.account_id=y.account_id) + INTERVAL
CASE return_period
when 'L3M' then -2
when 'YTD' then -1
when '1YR_CUM' then -11
when '1YR_ANN' then -11
when '2YR_CUM' then -23
when '2YR_ANN' then -23
when '3YR_CUM' then -35
when '3YR_ANN' then -35
when '4YR_CUM' then -47
when '4YR_ANN' then -47
# [...]
END
MONTH),
end_date=(select max(monthend_date) from returns y WHERE x.account_id=y.account_id);
为什么你不能创建一个数据库表来充当这些值的查找并使用'JOIN'?这是一大堆SQL。 – tadman