C# Winform - How do i show Data from Multiple Tables in Datagridview

Curriculum table

CurriculumID (PK, auto-increment)

CurriculumName Varchar(255)

GradeLevel table

GradeLevelID (PK, auto-increment)

GradeLevel Varchar(255)

CurriculumID (foreign key to Curriculum)

SubjectCreator table

SubjectID(PK, auto-increment)

SubjectName Varchar(255)

SubjectDescription Varchar(255)

GradeLevelID (foreign key to GradeLevel)

So Far these are my codes

i don't know the Query to show 3 tables. only tried 2 Tables.

these are the codes for 2 tables.



string sql = "select GradeLevelID, GradeLevelName, CurriculumName from GradeLevelCreator inner join CurriculumCreator on GradeLevelCreator.CurriculumID = CurriculumCreator.CurriculumID";

string connectionString = "Data Source=TOSHIBA-PC\\KENNETH;Initial Catalog=HSPAEnrollmentSystem;Integrated Security=True";
            string sql = "";
            SqlConnection connection = new SqlConnection(connectionString);
            SqlDataAdapter dataadapter = new SqlDataAdapter(sql, connection);
            DataSet ds = new DataSet();
            connection.Open();
            dataadapter.Fill(ds, "GradeLevelCreator");
            connection.Close();
            dataGridView1.DataSource = ds;
            dataGridView1.DataMember = "GradeLevelCreator";

i think i just need the query to Show multiple or 3 tables. Thank you in advance!