如何在android sqlite中编写连接查询？

Question

嗨，我是新来的android。我想在sqlite中编写连接查询。我的代码是 -

public Cursor SearchCategory(SQLiteDatabase db){ 
     //return db.query("category_master", null, "status = 'Active'", null, null, null, null); 

     String Category_Sql = " select category_master.*,count(*) as cnt from product_master " + 
          " left join category_master on product_master.category_id = category_master.category_id " + 
          " where category_master.status = 'Active' group by category_master.category_id having cnt > 0 "; 
     return db.query(Category_Sql); 
    } 

但它会产生错误。我错在哪里？

Answer 1

如果你能引用错误描述，它会有更多的帮助。

尝试在Portable SQLite explorer

Answer 2

首先运行查询，你可以使用rawQuery

db.rawQuery("Select a.column1,b.column1 FROM table1 a JOIN table2 b ON a._id=b._id", null); 

它应该工作