Hi lingers,

You have to use below query to select multiple PosiNo.

SELECT Id,PosiNo FROM job_cylinder WHERE PosiNo IN (SELECT PosiNo FROM job_cylinder WHERE PId = '568') AND PosiNo <> '' ORDER BY unit DESC

Then use the result to save in Session.

Query

DECLARE @job_cylinder AS TABLE (Id INT,PId INT,PosiNo VARCHAR(50),Colour VARCHAR(10),Direction VARCHAR(10),Circumference VARCHAR(10),Unit VARCHAR(10))
INSERT INTO @job_cylinder VALUES(5591,568,'','','','',1)
INSERT INTO @job_cylinder VALUES(5592,568,'','','','',2)
INSERT INTO @job_cylinder VALUES(5593,568,'50108102-A1','SILVER','0.5','686.823',3)
INSERT INTO @job_cylinder VALUES(5594,568,'50108111-A2','MAGENTA','0.4','686.823',4)
INSERT INTO @job_cylinder VALUES(5595,568,'50108111-3A','DEMI','0.3','686.823',5)
INSERT INTO @job_cylinder VALUES(5596,568,'50108111-4A','SPOT','0.2','686.823',6)
INSERT INTO @job_cylinder VALUES(5597,568,'50108111-5A','BLUE','0.1','686.823',7)
INSERT INTO @job_cylinder VALUES(5598,568,'50108111-6A','BLACK','0.1','686.823',8)
INSERT INTO @job_cylinder VALUES(5599,568,'50108111-7A','SEMI','0','686.823',9)
INSERT INTO @job_cylinder VALUES(5600,568,'50108102-8A','STRUCTURAL','0','686.823',10)
INSERT INTO @job_cylinder VALUES(5603,569,'50108102-A1','SILVER','0.5','686.823',3)

SELECT Id,PosiNo FROM @job_cylinder WHERE PosiNo IN (SELECT PosiNo FROM @job_cylinder WHERE PId = '568') AND PosiNo <> '' ORDER BY unit DESC

Code

string selectSQL1;
selectSQL1 = "SELECT Id,PosiNo FROM job_cylinder WHERE PosiNo IN (SELECT PosiNo FROM job_cylinder WHERE PId = '568') AND PosiNo <> '' ORDER BY unit DESC";
dbConn2.ConnectionString = "Data Source=NERE\\SQLEXPRESS01; Initial Catalog=kaging;Integrated Security=True;";
cmd2.Connection = dbConn2;
cmd2.CommandText = selectSQL1;
cmd2.CommandType = CommandType.Text;
dbConn2.Open();
dr2 = cmd2.ExecuteReader();
List<string> posinos = new List<string>();
while (dr2.Read())
{
    posinos.Add(dr2["posino"].ToString());
}
Session["hj"] = posinos;
dbConn2.Close();