kylin計算兩列時間相差天數

select TIMESTAMPDIFF(day,date'2012-01-01', date '2014-02-01')

執行結果：

*****_EXTERNAL兩列時間 ADMISSION_TIME和DISCHARGE_TIME 爲varchar類型：

查詢*****_EXTERNAL表數據：

select * from ***_EXTERNAL where VISIT_ID='2626780';

執行sql

select TIMESTAMPDIFF(day, CAST(ADMISSION_TIME AS timestamp),CAST(DISCHARGE_TIME AS timestamp))  from ***_EXTERNAL where VISIT_ID='2626780';

執行結果：