[英]SQL Teradata evaluation order of case when then else
我想在適用於VMware Player的正式Teradata Express上運行此查詢(帶有Viewpoint的VMware(40GB)的TDE 15.00.01 SLES 10):
SELECT 'MaxValue' column_name,
COUNT("MaxValue") AS count_value,
COUNT(DISTINCT("MaxValue")) AS count_dist_value,
MIN("MaxValue") AS min_value,
MAX("MaxValue") AS max_value,
CASE WHEN max_value > 99999999999999 THEN 99999999999999
ELSE SUM("MaxValue") END AS sum_value
FROM (SELECT TOP 100 * FROM "DBC"."IdCol") AS xy;
但是我得到這個錯誤:
作為單條語句執行。 失敗[2616:22003]計算期間發生數值溢出。 經過的時間= 00:00:00.115
陳述1:選擇陳述式失敗。
所以我的問題是,當CASE邏輯為True時,為什么要評估ELSE語句? 以及如何運行此查詢? 我想要來自未知表的COUNT,MIN,MAX,AVG,SUM等信息,我不知道一列是否包含20位長數字。 謝謝!
根據DrCopyPaste的評論,解決方案是:
SELECT 'MaxValue' column_name,
COUNT("MaxValue") AS count_value,
COUNT(DISTINCT("MaxValue")) AS count_dist_value,
MIN("MaxValue") AS min_value,
MAX("MaxValue") AS max_value,
CASE WHEN max_value > 99999999999999 THEN 99999999999999
ELSE SUM(CAST("MaxValue" AS BIGINT)) END AS sum_value
FROM (SELECT TOP 100 * FROM "DBC"."IdCol") AS xy;
謝謝!
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