Javascript 如何从两个表中选择一个属性？

朋友们，我有两个表BrandCategories和BrandOffers。两个表都有一个列名“brandId”。现在，我正在使用我在下面编写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"

我想在一个包含两个表的结果的查询中选择brandId？？我怎么做

我尝试了以下书面查询

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

请告诉我我是对还是错

在我的程序中，我编写了如下内容：

    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);

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如果要获得两个查询的不同值，请使用

union

；如果要获得两个查询的所有结果，请使用

union all

（这可能会导致重复）：

---

你可以用UNION来做这个

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

UNION是一种书写UNION DISTINCE的较短方法。 如果要同时获取两个表中的键，请使用UNION ALL

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

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告诉我们您是否得到了正确的结果。04-02 14:08:13.052:E/SQLiteLog（28112）：（1）靠近“（”：语法错误我到目前为止收到了这个错误，我只想得到那些具有折扣类型=“selectedDiscountType”的brandId，但它们必须在类别中。Union正在合并整个结果我只想得到那些具有折扣类型=“selectedDiscountType”，但它们必须在类别中..Union正在合并整个结果-

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