Question

所以我试图在我的sql命令中使用INNER JOIN，因为我试图用每列的文本值替换外键ID号。但是，当我使用INNER JOIN时，“Standards”的列总是给我相同的值。以下是我开始的内容

SELECT Grade_Id, Cluster_Eng_Id, Domain_Math_Eng_Id, Standard 
FROM `math_standards_eng` 
WHERE 1

并返回此（这很好）。请注意，标准值的值是不同的

 Grade_Id   Cluster_Eng_Id  Domain_Math_Eng_Id  Standard
 103           131                 107          Explain equivalence of fractions in special cases...
 104           143                 105          Know relative sizes of measurement units within o...

当我尝试使用Inner Join时，Grade_Id，Cluster_Eng_Id和Domain_Math_Eng_Id的值会从数字更改为实际文本。但是，标准列值似乎返回相同的值。这是我的代码：

SELECT 
    grades_eng.Grade, domain_math_eng.Domain, cluster_eng.Cluster, 
    math_standards_eng.Standard 
FROM 
    math_standards_eng 
INNER JOIN 
    grades_eng ON math_standards_eng.Grade_Id = grades_eng.Id 
INNER JOIN 
    domain_math_eng ON math_standards_eng.Domain_Math_Eng_Id 
INNER JOIN 
    cluster_eng ON math_standards_eng.Cluster_Eng_Id

这是我运行查询时得到的结果：

Grade   Domain                       Cluster                                    Standard    
3rd     Counting and cardinality    Know number names and the count sequence    Explain equivalence of fractions in special cases...
3rd     Expressions and Equations   Know number names and the count sequence    Explain equivalence of fractions in special cases...
3rd     Functions                  Know number names and the count sequence     Explain equivalence of fractions in special cases. 
4th     Counting and cardinality    Know number names and the count sequence    Know relative sizes of measurement units within o...
4th     Expressions and Equations   Know number names and the count sequence    Know relative sizes of measurement units within o...

标准的文本值继续显示每个等级的相同值，我不知道为什么。 3将继续显示相同的内容，然后下一个等级将更改为新值并反复重复。最后，每个表与标准具有1：M的关系，因为它们在标准表中多次出现。任何建议将不胜感激。

Answer 1

您错过了=和INNER JOIN上domain_math_eng的{{1}}部分。我希望有类似的东西：

cluster_eng

SQL查询失灵

1 个答案: