Clickhouse 时间格式化,字符串转日期,月初月末年初年末,dateDiff,row_number

Clickhouse大小写敏感，字段，表名，函数 

select
-- 日期相差天数(可选month/week/day/hour/minute/second)
dateDiff('day', toDate(now()),toDate(now())+3) days,
-- 当月第一天  toStartOfYear(),toMonday(),toStartOfQuarter()
toStartOfMonth(now()) start_month,
-- 当月月末
toStartOfMonth(addMonths(now(),1))-1 end_month,
-- 当年月末
toStartOfYear(addMonths(now(),12))-1 end_year,
-- 非日期格式字符串转日期
parseDateTimeBestEffort('20220427'),
toString(20220427),
toFloat32('20220427'),
ifnull(null,1)
toDate(now()),
formatDateTime(now(),'%Y%m%d')     yyyymmdd1,
toYYYYMMDD(now())     yyyymmdd2,
toYYYYMM(now())     yyyymm ,
toYear(now())     yyyy,
toMonth(now())     mm,
formatDateTime(now(),'%d')     dd