android - SQLITE CREATE VIEW JOIN 的语法问题

Question

当我尝试将 3 个表连接在一起时，在使用 JOIN 创建 View 时遇到了一些麻烦，我可以做 2 个表，但 3 个表对我来说似乎不行。我对此很陌生，所以我只是通过反复试验，因为我浏览过的大多数文档并没有真正涵盖(据我所知)连接 3 个表，而且进展并不顺利，所以我在这里一些建议并希望有一个解决方案。提前致谢。

以下是表格:

条款

db.execSQL("CREATE TABLE " + termsTable + " (" + colTermsID + " INTEGER PRIMARY KEY , " + colTermsClass + " TEXT)");

状态

  db.execSQL("CREATE TABLE " + statTable + " (" + colStatusID + " INTEGER PRIMARY KEY , " + colStatClass + " TEXT)");

账户

db.execSQL("CREATE TABLE " + accountsTable + " (" + colID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
            colName + " TEXT, " +
            colAmount + " Integer, " +
            colPurpose + " TEXT, " +
            colTerms +" INTEGER NOT NULL, " +
            colStatus +" INTEGER DEFAULT '1'," +
            colDate + " TEXT, " +
            "FOREIGN KEY (" + colTerms + ") REFERENCES " + termsTable + " (" + colTermsID + ") " + "," +
            "FOREIGN KEY (" + colStatus + ") REFERENCES " + statTable + " (" + colStatusID + "));");

这是我正在使用的创建 View ，它仅适用于条款或状态之一，但当我尝试使用两者时则不然，所以我认为我在该领域做错了什么。

    db.execSQL("CREATE VIEW " + viewAccs +
                    " AS SELECT " + accountsTable + "." + colID + " AS _id," +
                    " " + accountsTable + "." + colName + "," +
                    " " + accountsTable + "." + colAmount + "," +
                    " " + accountsTable + "." + colPurpose + "," +
                    " " + termsTable + "." + colTermsClass + "" +
                    " FROM " + accountsTable + " JOIN " + termsTable + " ON " + accountsTable + "." + colTerms + " = " + termsTable + "." + colTermsID +
                    " " + statTable + "." + colStatClass + "" +
                    " FROM " + accountsTable+ " JOIN " + statTable + " ON " + accountsTable + "." + colStatus + " = " + statTable + "." + colStatusID +
                    " " + accountsTable + "." + colDate
    );

编辑(在此回答):

这是我在修复语法并遵循 X.L Ant 提到的内容后最终得到的实际代码，供将来引用。

            db.execSQL("CREATE VIEW " + viewAccs +
                    " AS SELECT " + accountsTable + "." + colID + " AS _id," +
                    " " + accountsTable + "." + colName + "," +
                    " " + accountsTable + "." + colAmount + "," +
                    " " + accountsTable + "." + colPurpose + "," +
                    " " + termsTable + "." + colTermsClass + "," +
                    " " + statTable + "." + colStatClass + "," +
                    " " + accountsTable + "." + colDate + "" +
                    " FROM " + accountsTable +
                    " JOIN " + termsTable + " ON " + accountsTable + "." + colTerms + " = " + termsTable + "." + colTermsID +
                    " JOIN " + statTable + " ON " + accountsTable + "." + colStatus + " = " + statTable + "." + colStatusID
    );

Answer 1

一个查询中不能有两个 FROM。

试试这个:

db.execSQL("CREATE VIEW " + viewAccs +
                " AS SELECT " + accountsTable + "." + colID + " AS _id," +
                " " + accountsTable + "." + colName + "," +
                " " + accountsTable + "." + colAmount + "," +
                " " + accountsTable + "." + colPurpose + "," +
                " " + termsTable + "." + colTermsClass + "" +
                " FROM " + accountsTable + 
                " JOIN " + termsTable + " ON " + accountsTable + "." + colTerms + " = " + termsTable + "." + colTermsID +
                " " + statTable + "." + colStatClass + "" +
                " JOIN " + statTable + " ON " + accountsTable + "." + colStatus + " = " + statTable + "." + colStatusID +
                " " + accountsTable + "." + colDate

确保您在 SQL 中注入(inject)的变量是安全的，以避免注入(inject)。