在两个桌子上左联接

Question

I tried the following SQL query to load data from a database to PowerPivot model based on instructions from a PowerPivot manual:

SELECT
  Production_Product.Name AS Product,
  Production_ProductCategory.Name AS Category,
  Production_ProductSubcategory.Name AS SubCategory
FROM
  Production_Product
  LEFT OUTER JOIN Production_ProductSubcategory
    ON Production_Product.ProductSubcategoryID = Production_ProductSubcategory.ProductSubcategoryID
  LEFT OUTER JOIN Production_ProductCategory
    ON Production_ProductSubcategory.ProductCategoryID = Production_ProductCategory.ProductCategoryID

Unfortunatelly it keeps throwing a syntax error (missing operator) and I can't find what went wrong. It worked perfectly with only one (first) inner join.

Answer 1

Since you have not specified the RDBMS I would assume it is MS Access

Because the syntax of your query is standard SQL and is correct for all RDBMS but MS access, as you must surround several LEFT JOINs with parenthesis in Access

SELECT
  Production_Product.Name AS Product,
  Production_ProductCategory.Name AS Category,
  Production_ProductSubcategory.Name AS SubCategory
FROM
  ((Production_Product
  LEFT OUTER JOIN Production_ProductSubcategory
    ON Production_Product.ProductSubcategoryID = Production_ProductSubcategory.ProductSubcategoryID)
  LEFT OUTER JOIN Production_ProductCategory
    ON Production_ProductSubcategory.ProductCategoryID = Production_ProductCategory.ProductCategoryID)