Develop Reference

Rearrange DB query result in array for duplicate rows

I want to rearrange query result from db with duplicate data into distinct row (for data display )but having 1 column collect related values in comma separated if more than 1 item found.
For example consider list below (from db query):
ID GROUP DATE
A1212 1 1/1/2019
A1212 2 1/1/2019
A1313 1 3/1/2019
into:
ID GROUP
A1212 1,2
A1313 1
sql string:
select DISTINCT Declaration_Form_Master.*,Declaration_Form_Detail.KPA_Group, Temp_Storage_Reg_V.*,Temp_Storage_Reg_V.ID as TSEID,Users.Company As Uc, 'NULL' as 'CTU_id' from Declaration_Form_Master left outer join Temp_Storage_Reg_V on (Declaration_Form_Master.Master_ID=Temp_Storage_Reg_V.TSEMaster_ID) right join Users on (Declaration_Form_Master.Agent_ID = Users.UserId) right join Declaration_Form_Detail on (Declaration_Form_Master.Master_ID = Declaration_Form_Detail.Master_ID) where Declaration_Form_Master.Confirmation ='1' and Submit_Date >= '2019-01-28' and Submit_Date < '2019-08-30' order by Application_ID DESC
need to join all table because search criteria based on column on multiple table. i cant figure out on sql, but want to rearrange back the result using array or list.
Maybe some algorithm can help.

Try following :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
DataTable dt = new DataTable();
dt.Columns.Add("ID", typeof(string));
dt.Columns.Add("GROUP", typeof(int));
dt.Columns.Add("DATE", typeof(DateTime));
dt.Rows.Add(new object[] {"A1212", 1, DateTime.Parse("1/1/2019")});
dt.Rows.Add(new object[] {"A1212", 2, DateTime.Parse("1/1/2019")});
dt.Rows.Add(new object[] {"A1213", 1, DateTime.Parse("3/1/2019")});
DataTable dt2 = new DataTable();
dt2.Columns.Add("ID", typeof(string));
dt2.Columns.Add("GROUP", typeof(string));
var groups = dt.AsEnumerable().GroupBy(x => x.Field<string>("ID")).ToList();
foreach (var group in groups)
{
dt2.Rows.Add(new object[] {
group.Key,
string.Join(",", group.Select(x => x.Field<int>("GROUP").ToString()).Distinct())
});
}
}
}
}

If you want to do this action even in T-SQL you must aggregate the result
By exemple
DECLARE #fakeTable TABLE (ID varchar(50), [GROUP] int)
INSERT INTO #fakeTable
VALUES
('A1212', 1 ),
('A1212', 2 ),
('A1213', 1 )
SELECT
ID,
[GROUP] = stuff((
SELECT ','+convert(varchar(100),[GROUP])
FROM #fakeTable innerTable
WHERE innerTable.ID = orgTable.ID
ORDER BY [GROUP]
for xml path (''), type).value('.','nvarchar(max)')
,1,1,'')
FROM (
SELECT DISTINCT ID FROM #fakeTable
) orgTable
More info about aggregation

DataTable dx = new DataTable();
dx.Columns.Add("Application_ID", typeof(int));
dx.Columns.Add("KPA_Group", typeof(int));
foreach(var z in data) {
dx.Rows.Add(new object[] { z.Application_ID,z.KPA_Group });
}
DataTable dt1 = new DataTable();
dt1.Columns.Add("Application_ID", typeof(string));
dt1.Columns.Add("KPA_Group", typeof(string));
var groups = dx.AsEnumerable().GroupBy(x => x.Field<Int32>("Application_ID")).ToList();
foreach (var group in groups)
{
dt1.Rows.Add(new object[] {
group.Key,
string.Join(",", group.Select(x => x.Field<int>("KPA_Group").ToString()).Distinct())
});
}
foreach (DataRow row in dt1.Rows)
{
#:#row["Application_ID"].ToString() |
#:#row["KPA_Group"] <br />
}
result :
2019080001 | 2,3
2019070002 | 2
2019070001 | 2
2019060001 | 1,2
2019040002 | 2
2019030002 | 2
2019030001 | 2
2019020002 | 2
2019020001 | 2
i dont understand why i can't use CopyToDataTable method. solved this by using foreach.

How to find the count of distinct records in a MS Access database using C#?

I have an MS Access database as below
Filing_Year | Name
------------------------
02/01/2008 | AAA
02/01/2008 | AAA
02/03/2008 | AAA
03/01/2008 | BBB
I need a query in C# which will get me an output as below and display it in a gridview
Filing_Year | file_count
----------------------------
02/01/2008 | 2
02/03/2008 | 1
03/01/2008 | 1
This is the code I tried:
dataGridView1.Columns.Add("Column", "FileCount"); // file count is not an element in database
OleDbConnection con = new OleDbConnection(#"Provider=Microsoft.Jet.OLEDB.4.0;DataSource=|DataDirectory|\RMS_Database.mdb");
con.Open();
OleDbDataAdapter sda = new OleDbDataAdapter("select Filing_Year,count(*) from Checklist_Data group by Filing_Year ", con);
DataTable dt = new DataTable();
sda.Fill(dt);
BindingSource bSource = new BindingSource();
bSource.DataSource = dt;
dataGridView1.DataSource = bSource;
sda.Update(dt);
With this I am seeing only unique filing_year, but not the count.
Thanks in advance. Help is really appreciated.

You need to modify your SQL Query like:
SELECT Filing_Year, COUNT(Name) as file_count
FROM Checklist_Data
GROUP BY Filing_Year, Name

Datatable group and pivot

I have a DT with following structure
unit | value | date
-------------------------
A | 2 | 01-01-2000
B | 3 | 01-01-2000
A | 4 | 02-01-2000
I would like to transform it into following
| A | B
---------------------------
01-01-2000 | 2 | 3
02-01-2000 | 4 |
What would be the fastest way to achieve this?
EDIT:
I have implemented a function for pivot, which gives me the following:
| A | B | A
--------------------------------------
value | 2 | 3 | 4
date |01-01-2000|01-01-2000|02-01-2000
But in this case I am missing grouping by columns.
By 'fastest' I mean possibly shortest code to achieve this (LINQ?). Or perhaps pivot can be achieved simultaneously in the same query?

Try this
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
DataTable dt = new DataTable();
dt.Columns.Add("unit", typeof(string));
dt.Columns.Add("value", typeof(int));
dt.Columns.Add("date", typeof(DateTime));
dt.Rows.Add(new object[] { "A",2, DateTime.Parse("01-01-2000")});
dt.Rows.Add(new object[] { "B",3, DateTime.Parse("01-01-2000")});
dt.Rows.Add(new object[] { "A",4, DateTime.Parse("02-01-2000")});
string[] uniqueUnits = dt.AsEnumerable().Select(x => x.Field<string>("unit")).Distinct().ToArray();
DataTable dt1 = new DataTable();
dt1.Columns.Add("date", typeof(DateTime));
foreach (string unit in uniqueUnits)
{
dt1.Columns.Add(unit, typeof(int));
}
var groups = dt.AsEnumerable().GroupBy(x => x.Field<DateTime>("date"));
foreach (var group in groups)
{
DataRow newRow = dt1.Rows.Add();
foreach (DataRow row in group)
{
newRow["date"] = group.Key;
newRow[row.Field<string>("unit")] = row.Field<int>("value");
}
}
}
}
}

It's more lines of code but can be done with only one loop as well:
DataTable dt1 = new DataTable();
dt1.Columns.Add(new DataColumn("unit",typeof(string)));
dt1.Columns.Add(new DataColumn("value",typeof(int)));
dt1.Columns.Add(new DataColumn("date",typeof(DateTime)));
dt1.Rows.Add(new object[] { "A", 2, DateTime.Parse("01-01-2000") });
dt1.Rows.Add(new object[] { "B", 3, DateTime.Parse("01-01-2000") });
dt1.Rows.Add(new object[] { "A", 4, DateTime.Parse("02-01-2000") });
DataTable dt2 = new DataTable();
dt2.Columns.Add(new DataColumn("date", typeof(DateTime)));
dt2.PrimaryKey = new DataColumn[] { dt2.Columns["date"], };
List<string> cols = new List<string>();
List<DateTime> ds = new List<DateTime>();
foreach (DataRow dr1 in dt1.Rows)
{
string unit = dr1["unit"].ToString();
if (!cols.Contains(unit))
{
dt2.Columns.Add(new DataColumn(unit, typeof(int)));
cols.Add(unit);
}
DateTime pkDate = (DateTime)dr1["date"];
if (!ds.Contains(pkDate))
{
ds.Add(pkDate);
DataRow dr = dt2.NewRow();
dr["date"] = dr1["date"];
dr[unit] = dr1["value"];
dt2.Rows.Add(dr);
}
else
{
dt2.Rows.Find(pkDate)[unit] = dr1["value"];
}
}

How to edit/update in dynamic table

I have dynamic DataTable says to be DataTable dt=New DataTable(); and column name says to be ID, F_name, L_name.
I had fill a value to this column seems to be
ID | F_name | L_name
1 | mit | jain
2 | raj | patel
3 | anki | patel
4 | alpa | dumadiya
If I want to edit/update column 2 says to be ID=2, F_name that is raj to rajan
what shall I have to do?

You can try like this :
static void Main(string[] args)
{
DataTable dt = GetTable();
DataRow[] dr = dt.Select("ID=2 and F_Name='raj'");
if (dr !=null)
{
foreach (var item in dr)
{
item["F_name"] = "rajan";
}
}
}
static DataTable GetTable()
{
DataTable dt = new DataTable();
dt.Columns.Add("ID");
dt.Columns.Add("F_name");
dt.Columns.Add("L_name");
dt.Rows.Add("1", "mit", "jain");
dt.Rows.Add("2", "raj", "patel");
dt.Rows.Add("3", "anki", "patel");
dt.Rows.Add("4", "alpa", "dumadiya");
return dt;
}

Add columns of datatables in a dataset

I have a DataSet with 2 DataTable's. Each DataTable contains a column called "cost".
I want to calculate the sum of all costs for the 2 tables in a table called Result table, like the example below. How can I do that?
Table 1
Name | cost
balan | 6
gt | 5
Table 2
Name | cost
balan | 2
gt | 8
Result table
Name | cost
balan | 8
gt | 12

This is a way to do it:
DataTable dt1 = new DataTable();
DataTable dt2 = new DataTable();
DataTable results = new DataTable();
dt1.Columns.Add("Name");
dt1.Columns.Add("cost", typeof(int));
dt2.Columns.Add("Name");
dt2.Columns.Add("cost", typeof(int));
results.Columns.Add("Name");
results.Columns.Add("cost", typeof(int));
dt1.Rows.Add("balan", 6);
dt2.Rows.Add("balan", 2);
dt1.Rows.Add("gt", 5);
dt2.Rows.Add("gt", 8);
foreach (DataRow dr1 in dt1.Rows)
{
results.Rows
.Add(
dr1["Name"],
(int)dr1["cost"] + (int)dt2.Select(String.Format("Name='{0}'", dr1["name"]))[0]["cost"]
);
}

to get the result, you can do something like
var table1 = yourDataSet.Tables["Table 1"];
var table2 = yourDataSet.Tables["Table 2"];
var results = table1.AsEnumerable().Select(t1 => new {
name = t1.Field<string>("Name"),
cost = t1.Field<int>("cost")
})
.Concat(
table2.AsEnumerable().Select(t2 => new {
name = t2.Field<string>("Name"),
cost = t2.Field<int>("cost")
})
)
.GroupBy(m => m.name)
.Select(g => new {
name = g.Key,
cost = g.Sum(x => x.cost)
});
this won't give you a dataTable, but an IEnumerable. To transform an IEnumerable to a dataTable, see for example here
or easier, if table1 and table2 have same rows
var table1 = yourDataSet.Tables["Table 1"];
var table2 = yourDataSet.Tables["Table 2"];
var results = new DataTable();
results.Columns.Add("Name");
results.Columns.Add("cost", typeof(int));
table1.AsEnumerable().Concat(table2.AsEnumerable())
.GroupBy(m => m.Field<string>("Name"))
.Select(g => results.Rows.Add(g.Key, g.Sum(x => x.Field<int>("cost"))));