teradata SQL CASE WHEN - SELECT 失败。 3771: CASE 表达式的 WHEN 子句中有非法表达式答案

【问题标题】：teradata SQL CASE WHEN - SELECT Failed. 3771: Illegal expression in WHEN clause of CASE expressionteradata SQL CASE WHEN - SELECT 失败。 3771: CASE 表达式的 WHEN 子句中有非法表达式
【发布时间】：2021-03-26 10:20:42
【问题描述】：

我正在尝试按不同类型的时间段对数据进行分组，但我没有这样做。我想将这些时间段命名为“入职”和“生活中”，但 Terdata 不会让我这样做。有谁知道为什么它一直在喊我的 when 子句是非法的？

SELECT
CASE 
MONTHS_BETWEEN (business_dt, CAST(LOYALITY_START_DATE_CRM AS DATE))
WHEN 
MONTHS_BETWEEN (business_dt, CAST(LOYALITY_START_DATE_CRM AS DATE)) > 0 
AND
MONTHS_BETWEEN (business_dt, CAST(LOYALITY_START_DATE_CRM AS DATE)) < 3 then 'onboarding' 
WHEN 
MONTHS_BETWEEN (business_dt, CAST(LOYALITY_START_DATE_CRM AS DATE)) > 3 
AND 
MONTHS_BETWEEN (business_dt, CAST(LOYALITY_START_DATE_CRM AS DATE)) < 18 then 'in-life' 
else 'eop'
END AS life_cycle,
COUNT (*) Number_of_contracts
FROM
VT_DM_CUMULATIVE_EXT.mobile_events
GROUP BY
life_cycle
WHERE
business_dt='2020-11-30'
;

请帮助

【问题讨论】：

标签： sql select teradata case-when

【解决方案1】：

您正在结合简单和搜索的案例陈述。去掉第一个 MONTHS_BETWEEN 子句。

SELECT
CASE 
WHEN 
MONTHS_BETWEEN (business_dt, CAST(LOYALITY_START_DATE_CRM AS DATE)) > 0 
AND
MONTHS_BETWEEN (business_dt, CAST(LOYALITY_START_DATE_CRM AS DATE)) < 3 then 'onboarding'
...

【讨论】：