在另一個計算中使用產品 - SQL select語句

Question

這是我冗長的SQL代碼。我基本上試圖將數據庫信息首先從每月，每日和每年費率轉換爲每小時。然後將此小時數轉換爲美元，如果它尚未。

到目前爲止，我已將兌換率轉換爲「兌換率」，但在轉換爲美元時如何使用此新兌換率？即在：

WHEN wo.currency = 'GBP' 然後（wo.avg_rate * 1.66）

我不能改變wo.avg_rate要麼wo.converted_rate，x.converted_rate， 「轉化率，」 或「轉化率。'我怎樣才能做到這一點 ？

SELECT 
    x.work_order_ref as 'Work Order Reference' 
    ,x.buyer_code as 'Buyer Code' 
    ,x.submit_time as 'Work Order Submit Time' 
    ,x.rate_unit_for_spend_calc as 'UOM' 
    ,x.avg_rate as 'ST Rate' 
    ,x.converted_rate as 'Converted Rate' 
    ,x.currency as 'Currency' 
    ,x.converted_amount AS 'Converted Amount' 
    ,jp.title AS 'JP Title' 
    ,lbt.name AS 'Labor Type' 
    ,jp.max_distribution_level AS 'Max Distr Level' 
    ,si.city AS 'City' 
    ,si.state_province as 'State' 
    ,si.country AS 'Country' 
    ,ctg.name AS 'Category' 
    ,count(jpd.supplier_code) as 'Suppliers' 
from 
(select 
     wo.work_order_ref 
     ,wo.buyer_code 
     ,wo.submit_time 
     ,wo.rate_unit_for_spend_calc 
     ,"converted_rate" = 
         CASE 
         WHEN wo.rate_unit_for_spend_calc='Hr' then wo.avg_rate 
         WHEN wo.rate_unit_for_spend_calc='MO' then (wo.avg_rate/173.333) 
         WHEN wo.rate_unit_for_spend_calc='Day' then (wo.avg_rate/8) 
         WHEN wo.rate_unit_for_spend_calc='Yr' then (wo.avg_rate/2080) 
         END 
     ,wo.avg_rate 
     ,wo.currency 
     ,wo.job_posting_id 
     ,wo.site_id 
     ,wo.worker_id 
     ,wo.uploaded_flag 
     ,wo.sequence 
     ,"converted_amount" = 
         CASE 
         WHEN wo.currency='USD' then (wo.avg_rate) 
         WHEN wo.currency='GBP' then (wo.avg_rate*1.66) 
         WHEN wo.currency='SEK' then (wo.avg_rate*0.14) 
         WHEN wo.currency='EUR' then (wo.avg_rate*1.31) 
         WHEN wo.currency='CAD' then (wo.avg_rate*0.92) 
         WHEN wo.currency='AUD' then (wo.avg_rate*0.93) 
         WHEN wo.currency='INR' then (wo.avg_rate*0.017) 
         WHEN wo.currency='MXN' then (wo.avg_rate*0.076) 
         WHEN wo.currency='COP' then (wo.avg_rate*0.00052) 
         WHEN wo.currency='BRL' then (wo.avg_rate*0.44) 
         WHEN wo.currency='MYR' then (wo.avg_rate*0.32) 
         WHEN wo.currency='CNY' then (wo.avg_rate*0.16) 
         WHEN wo.currency='RON' then (wo.avg_rate*0.3) 
         WHEN wo.currency='CZK' then (wo.avg_rate*0.047) 
         WHEN wo.currency='SGD' then (wo.avg_rate*0.8) 
         WHEN wo.currency='PLN' then (wo.avg_rate*0.31) 
         WHEN wo.currency='JPY' then (wo.avg_rate*0.0096) 
         WHEN wo.currency='NZD' then (wo.avg_rate*0.84) 
         WHEN wo.currency='CHF' then (wo.avg_rate*1.09) 
         --ELSE (wo.avg_rate*x.conversion_factor) 
         END 
    from work_order wo(nolock)) as x 

...

如果它使它更好地爲我發佈完整的代碼和/或什麼我得到的，我能做到這一點。

Answer 1

如果您將轉換存儲在表中，它將使查詢變得更加容易。你甚至可以擺脫內部查詢：

declare @uom table (
    unit char(3) not null primary key, 
    divisor decimal(10, 5) not null 
); 

insert into @uom values 
    ('Hr', 1), ('MO', 173.333), ('Day', 8), ('Yr', 2080); 

declare @rate table (
    currency char(3) not null primary key, 
    usd_mult decimal(10, 5) not null 
); 

insert into @rate values 
    ('USD', 1), ('GBP', 1.66), ('SEK', 0.14), ('EUR', 1.31), 
    ('CAD', 0.92), ('AUD', 0.93), ('INR', 0.017), ('MXN', 0.076), 
    ('COP', 0.00052), ('BRL', 0.44), ('MYR', 0.32), ('CNY', 0.16), 
    ('RON', 0.3), ('CZK', 0.047), ('SGD', 0.8), ('PLN', 0.31), 
    ('JPY', 0.0096), ('NZD', 0.84), ('CHF', 1.09); 

select 
    wo.work_order_ref, 
    wo.buyer_code, 
    wo.submit_time, 
    wo.rate_unit_for_spend_calc, 
    wo.avg_rate/u.dividend as converted_rate, 
    wo.avg_rate, 
    wo.currency, 
    wo.job_posting_id, 
    wo.site_id, 
    wo.worker_id, 
    wo.uploaded_flag, 
    wo.sequence, 
    -- is this where you wanted converted_rate * currency_mult? 
    wo.avg_rate/u.dividend * r.usd_mult as converted_amount 
from 
    work_order wo with (nolock) 
     inner join 
    @uom u 
     on wo.rate_unit_for_spend_calc = u.unit 
     inner join 
    @rate r 
     on wo.currency = r.currency 
) 

如果沒有這樣做，你可以隱藏功能後面的計算。這使事情變得更容易閱讀，但可以減緩查詢，爲優化器通過功能看到的麻煩：

create function dbo.HourlyRate(@unit as char(3), @rate as decimal(10, 5)) returns decimal(10, 5) as 
begin 
    return case @unit 
     when 'Hr' then @rate 
     when 'MO' then @rate/173.333 
     when 'Day' then @rate/8 
     when 'Yr' then @rate/2080 
    end 
end 

create function dbo.ConvertToUSD(@currency as char(3), @amount as decimal(20, 5)) returns decimal(20, 5) as 
begin 
    return case @currency 
     when 'USD' then @amount 
     when 'GBP' then @amount * 1.66 
     ... 
    end 
end 

說它像這樣：

select 
    ... 
    dbo.HourlyRate(wo.rate_unit_for_spend_calc, wo.avg_rate) as converted_rate, 
    ... 
    dbo.ConvertToUSD(wo.currency, dbo.HourlyRate(wo.rate_unit_for_spend_calc, wo_avg_rate) as converted_amount, 
    ... 
from 
    work_order wo with (nolock)