JOIN 操作语法错误 运行时错误'-2147217900 (80040e14)'

Dim sql As String
Dim rs As ADODB.Recordset       '声明ADO记录集对象
Set rs = New ADODB.Recordset '实例化记录集对象


sql = " SELECT BFRQ.拜访日,BFRQ.投保人CID,System_MapDay.MOTH FROM " _
& " ( " _
& " ( SELECT Record.CID,Record.建档日期 AS 拜访日 FROM Record WHERE (Record.CID LIKE  '" & USer & "%') AND (Record.建档日期<>Record.完成再访) ) " _
& " UNION ALL " _
& " ( SELECT Record.CID,Record.完成再访 AS 拜访日 FROM Record WHERE ( Record.CID LIKE '" & USer & "%' ) AND ( Record.完成再访 IS NOT NULL ) )" _
& " UNION ALL " _
& " ( SELECT BD.投保人CID,CustomRenPolicy10.崔访日期 AS 拜访日 FROM " _
& " ( SELECT CustomRenPolicy.投保人CID,CustomRenPolicy.ID FROM CustomRenPolicy WHERE CustomRenPolicy.投保人CID LIKE  '" & USer & "%' ) AS BD " _
& "   LEFT JOIN CustomRenPolicy10 ON BD.ID=CustomRenPolicy10.保单ID WHERE CustomRenPolicy10.崔访日期 IS NOT NULL  ) " _
& "  ) AS BFRQ " _

& " LEFT JOIN System_MapDay  ON BFRQ.拜访日=System_MapDay.Day  "

其中 绿色部分 是经过测试运行没问题的。可以一旦加上 下一个左连接，就一直提示 【 JOIN 操作语法错误  运行时错误'-2147217900 (80040e14)' 】。 一直怀疑是某处 括号的问题，找了几天也没过关

请各位大侠、老师指教！