mysql--clickhouse语法差异

  Mysql 7天前 　　concat(substr(date_sub(now(),interval 7 day),1,10),' 00:00:00') Clickhouse 7天前 　　select subtractDays(now(),7) MySQL 字符串类型求和 　　sum(CONVERT(host_name_counts,SIGNED)) Clickhouse 字符串类型求和 　　SUM(toDecimal32OrZero(host_name_counts,2))