左外连接访问？

Question

以下查询在访问中不起作用。

SELECT Fields.FieldId, PrecisionSettings.DecimalPlaces 

    from Fields left outer join FieldGroup on Fields.FieldGroupId = FieldGroup.FieldGroupId 

    left outer join Category on FieldGroup.CategoryId = Category.CategoryId 

    left outer join PrecisionSettings on 

    Category.InputAttributesID=PrecisionSettings.AttributesID 

它给错误在查询表达式缺少操作员。

Answer 1

在Access中，您一次只能加入两个结果。要加入更多表格，您需要更多圆括号：

SELECT Fields.FieldId, PrecisionSettings.DecimalPlaces 
    from 
     (
     (
      Fields left outer join FieldGroup on Fields.FieldGroupId = FieldGroup.FieldGroupId 
     ) 
     left outer join Category on FieldGroup.CategoryId = Category.CategoryId 
    ) 
     left outer join PrecisionSettings on Category.InputAttributesID=PrecisionSettings.AttributesID