IIF in postgres

Question

我在嘗試將MS-Access查詢轉換爲postgres語句，以便我可以在SSRS中使用它。似乎工作很好，除了IIF聲明。

SELECT labor_sort_1.ncm_id 
,IIf(labor_sort_1.sortby_employeeid = 3721 
, ((labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 29 * labor_sort_1.number_of_ops) 
, IIf(labor_sort_1.sortby_employeeid = 3722 
    , ((labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 24 * labor_sort_1.number_of_ops) 
    , IIf(labor_sort_1.sortby_employeeid = 3755, ((labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 24 * labor_sort_1.number_of_ops) 
    , ((labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 17 * labor_sort_1.number_of_ops)))) AS labor_cost 
FROM 
(SELECT 
ls_sort.ncm_id 
, ls_sort.computer_name 
, ls_sort.number_of_ops 
, ls_sort.badge_scan_time 
, ls_sort.sortby_employeeid 
, Min(ls_sort.ncm_scan_time) AS MinNCMScanTime 
, Max(ls_sort.updated_at) AS MaxUpdatedAt 
FROM stone.ls_sort 
INNER JOIN stone.ls ON ls_sort.ls_id = ls.ls_id 
WHERE 1=1 
AND ls_sort.created_at Between current_date-1 And current_date 
GROUP BY ls_sort.ncm_id 
, ls_sort.computer_name 
, ls_sort.number_of_ops 
, ls_sort.badge_scan_time 
, ls_sort.sortby_employeeid 
ORDER BY ls_sort.computer_name) AS labor_sort_1 

它返回以下消息 function iif(boolean, interval, interval) does not exist 我將如何解決這個問題？

Answer 1

您需要將邏輯切換到CASE語句。 CASE語句對於大多數RDBMS是標準的，所以值得學習。在你的情況（雙關語意），它會轉換成：

CASE 
    WHEN labor_sort_1.sortby_employeeid = 3721 
     THEN (labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 29 * labor_sort_1.number_of_ops 
    WHEN labor_sort_1.sortby_employeeid = 3722 
     THEN (labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 24 * labor_sort_1.number_of_ops 
    WHEN labor_sort_1.sortby_employeeid = 3755 
     THEN (labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 24 * labor_sort_1.number_of_ops 
    ELSE 
     (labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 17 * labor_sort_1.number_of_ops) 
    END AS labor_cost 

這是很多清潔期待，因爲你不必用嵌套iif()問題猴和這一切，你應該需要添加更多的僱員的到硬編碼勞動力成本清單，這並不是什麼大問題。

您也可以在這裏找到對我們有利的IN條件，所以你只需要兩個WHEN條款：

CASE 
    WHEN labor_sort_1.sortby_employeeid = 3721 
     THEN (labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 29 * labor_sort_1.number_of_ops 
    WHEN labor_sort_1.sortby_employeeid IN (3722, 3755) 
     THEN (labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 24 * labor_sort_1.number_of_ops 
    ELSE 
     (labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) * 24 * 17 * labor_sort_1.number_of_ops) 
    END AS labor_cost 

此外，您可以移動CASE語句插入的公式，只是把出什麼號碼，你希望乘以：

(labor_sort_1.MaxUpdatedAt - labor_sort_1.MinNCMScanTime) 
    * 24  
    * CASE 
     WHEN labor_sort_1.sortby_employeeid = 3721 THEN 29 
     WHEN labor_sort_1.sortby_employeeid IN (3722,3755) THEN 24 
     ELSE 17 
     END 
    * labor_sort_1.number_of_ops AS labor_cost