我在DolphinDB中执行下列代码:
db = database("dfs://transport")
tb = select top 1000 * from db.loadTable(`autos)
select concat(concat(concat(string(yearOfRegistration),"."),string(monthOfRegistration)),".01") as newcat from tb
报错:The second argument for 'concat' must be a string or a char。其中yearOfRegistration和monthOfRegistration两个字段的类型都是INT。数据如下图所示:
请问怎么解决?
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