SSIS update a column with a result of an sql select - sql

Question

I was wondering if there's a way of updating a column inside a dataflow task by running a select on every row?
Here's the situation :
Let's take this as our start position. I collect info from 2 files, then I merge them, and I add a column with the derived column tool. Is there a way of populating this column by performing a select on every row using the values of the the row?
Ex :
SELECT Count(*) AS cnt
FROM TABLE T
WHERE T.COLUMN1 = ROW.COLUMN3
AND T.COLUMN2 = ROW.COLUMN5
I don't know if I'm just not phrasing my need properly but I couldn't get any results
Thank you

Answer 1

You should be able to do this with a Lookup Transformation.
EDIT based on comment:
If you don't want to use a lookup due to the size of the table, you can do exactly what you want with a Script Component. You can create and execute your SQL Command for each row of the dataflow just like you would in any .net application.

Answer 2

I was able to do it with a Script Component
1- I've removed the Derived Column
2- I've created a string variable where I stored the query whith a wildcard string to replace every value that I need to get from the row.
3- I've passed this variable allong with one containing the connecection string info to the Script Component
4- I've added a new column to the Output Columns of the Script Component
5- Added using System.Data.OleDb;
6- Created 2 variables :
string jourFerieQuery;
string dbcsoledbschema;
7- Updated the PostExecute() to put the values of my SSIS variables into the script variables :
public override void PostExecute()
{
base.PostExecute();
jourFerieQuery = Variables.jourFerieQuery;
dbcsoledbschema = Variables.dbcsoledbschema;
}
8- Added a method :
int GetData(string cs, string query)
{
OleDbConnection conn = new OleDbConnection(cs);
conn.Open();
OleDbCommand cmd = new OleDbCommand(query, conn);
DataTable dt = new DataTable();
dt.Load(cmd.ExecuteReader());
conn.Close();
return (int)dt.Rows[0][0];
}
9- Updated the Input0_ProcessInputRow(Input0Buffer Row) :
public override void Input0_ProcessInputRow(Input0Buffer Row)
{
string query = jourFerieQuery.Replace("[1]", Row.CODDEVI).Replace("[2]", Row.DATCRBEZEROCONGE.ToString());
Row.Keep = GetData(dbcsoledbschema, query);
}
My query returns a count that's why the method I've added returns an int

Answer 3

You can do that through a script component (transformation).
Add an output of Ct.
I use System.Data.OleDB as it matches the SSIS package connection string.