这个SQL有什么问题？

Question

SQL是:

execute ('delete from HttpRequests where Date < ''2009-08-' + convert(nvarchar(max), 0) + '''')

错误是

Msg 156, Level 15, State 1, Line 1
Incorrect syntax near the keyword 'convert'.

注释掉转换部分会删除错误.怎么了？

Answer 1

将"执行"替换为"打印",删除括号,然后运行,即可获得

delete from HttpRequests where Date < '2009-08-0'

那不是一个有效的日期.