Question

朋友我有两张桌子BrandCategories和BrandOffers。两个表都有一个列名＆＃34; brandId＆＃34;。现在我正在使用我在下面写过的两个独立查询来选择brandId。

Select brandId from BrandCategories where categoryId   = "selectedCategory" AND isDeleted=0
Select brandId from BrandOffers     where discountType = "selectedDiscountType"

我想在一个查询中选择brandId，其中包含两个表的结果？我怎么能这样做？

我尝试过以下书面查询

SELECT brandId FROM BRANDCATEGORIES INNER JOIN BRANDOFFERS on BRANDCATEGORIES.brandId = BRANDOFFERS.brandId where BRANDCATEGORIES.categoryId='+brandCategorySelected+' AND BRANDOFFERS.discountTypeArabic="'+$('#DiscountDrop').val()+'" AND BRANDCATEGORIES.isDeleted=0

请告诉我是错还是对吗？

在我的程序中，我写了如下：

    db.transaction(function(tx) {tx.executeSql('(SELECT brandId FROM BRANDCATEGORIES INNER JOIN BRANDOFFERS on BRANDCATEGORIES.brandId = BRANDOFFERS.brandId where BRANDCATEGORIES.categoryId='+brandCategorySelected+' AND BRANDOFFERS.discountTypeArabic="'+$('#DiscountDrop').val()+'" AND BRANDCATEGORIES.isDeleted=0)', [], testing, errorCB);}, errorCB);

Answer 1

你可以使用UNION。

Select brandId from BrandCategories where categoryId   = "selectedCategory"
UNION
Select brandId from BrandOffers     where discountType = "selectedDiscountType"

UNION是编写UNION DISTINCT的较短方法。如果您还想获得两个表中的键，请使用UNION ALL

Select brandId from BrandCategories where categoryId   = "selectedCategory"
UNION ALL
Select brandId from BrandOffers     where discountType = "selectedDiscountType"

Answer 2

如果您希望获得两个查询的不同值，请使用union union all如果想要获得两个查询的所有结果（这可能会导致重复）：

Select brandId from BrandCategories where categoryId   = "selectedCategory"
union all
Select brandId from BrandOffers     where discountType = "selectedDiscountType"

如何从2个表中选择一个属性？

2 个答案: