This should be rather simple but I don't know why I get Row Count as Zero when I use ROW COUNT transformation in Data Flow Task. I have created a variable(NoOfRecords) with Package scope.
Variable name set to variable NoOfRecords in Row Count Transformation.
Used a Derived column to assign the row count.
The package runs successfully and shows record count 265
But the Derived column shows record count as 0 instead of 265 rows.
After the Row Count, add an Aggregate Taks and select count option in the Operation tab in the Aggregate task properties.
Then you can use the row count variable for further operation where it holds the total row count of the input file.
Row Count is processed after rows has passed.
You're adding the variable to each row as they pass through the Derived Column step, but at this time, the variable has not been updated (as it happens after all rows has passed) - so the value 0 is correct.
You -might- be able to achieve this by using an asynchronous task before your derived (but i'm not sure this'll work, it just popped to my mind). Add a Sort or Aggregate step before your Derived and try again.
I used this in the query as an efficient way of getting the row count:
count(all SnapshotDate) over () as nRowCount
Here's the successful technique for recording rows that worked in my situation.
The scenario is I want to log the rows migrated between tables. The RowCount doesn't get populated until you exit the DataFlow.
[Control Flow]
1. Data Flow Task
a. read origin data - Source control
b. Add RowCount transformation. Link a to b.
Right-click RowCount and map to UserVariable (int64)
c. Add Destination control for loading table.
d. Link b to c.
2. Add Execute SQL Task to ControlFlow. right click, edit
INSERT SQL statement: Insert Into LogTable(rowcount) Values(?)
Parameter Mapping
Variable Direction DataType ParameterName ParameterSize
User::RowCount INPUT LONG 0 -1
Related
The logic which we are trying to achieve in single query is as follows.
We need to loop based on row number column. So, on each loop we need to sum-up remaining value and new value.. resultant value to be updated in "by summing up column". and the decimal part to be updated in decimal value column.
in next step, need to sum-up the decimal value column by grouping on row number. and the resultant to be updated in remaining value column of next row number
the above step 1-2 to be continued till we reach last record.
We achieved this through while loop.. But trying to achieve this without while loop.
Can someone please give idea to achieve this
Please refer the attached image for understanding table
enter image description here
I have created 4 separate tables via sql code on sqlserver and I want to create one filter for all 4 using a common column i.e. month on power query. Usually, I would create 4 pivot tables and create 4 slicers for say, month. Can I dynamically create just one filter for the 4 pivots on PQ? I have seen examples of anti-joins but I don't see this working in my example. If any questions like this already exist, links to them will be much appreciated.
Cheers,
Mo
Table.SelectRows can takes a function as its second parameter, so you can create your filter function in one query and reference that query in the parameter.
For example, if I wanted to filter a column Value to only have numbers greater than 30, you would create a query with the following formula:
= (row) => row[Value] > 30
Let's call that query FilterValue. Then, if you wanted to use this filter on a table in step Step, you would add the following step (with the fx button next to the formula bar):
= Table.SelectRows(Step, FilterValue)
If you need to use the filter again in another query with the step OtherStep, add the following step:
= Table.SelectRows(OtherStep, FilterValue)
Any idea how to summarize data in a Pentaho transformation and then insert the summary row directly under the group being summarized.
I can use a Group By step and get a summarised result stream having one row per key field, but what I want is each sorted group written to the output and the summary row inserted underneath, thus preserving the input.
In the Group By, you can do 'Include all Rows', but this just appends the summary fields to the end of each existing row. It does not create new summary rows.
Thanks in advance
To get the summary rows to appear under the group by blocks you have to use some tricks, such as introducing a numeric "order" field, setting the value of the original data to 1 and the sub totals rows to 2.
Also in the group-by/ sub-totals stream, I am generating a sum field, say "subtotal". You have to make sure to also include this as a blank in your regular stream or else the metadata will be divergent and the final merge will not work.
Here is the best explanation I have found for this pattern:
https://www.packtpub.com/books/content/pentaho-data-integration-4-working-complex-data-flows
You will need to copy the rows too a different stream, and then merge or join them again, to make it a separate row.
May I ask how to count the row of tOracleInput and place it to the tOracleOutput. At the same time, can I add the values of that column SUM(tOracleOutput.OS_BALANCE)?
You could use the tAggregateRow component like this:
You should leave group by paramaters empty and create an output schema that will hold the sum and count. The row generated will then be fed to tOracleOutput.
I use a query which fetches say 50 records and passes it to a datatable. This record is then displayed in a tabular format. The display has pagination used displaying 10 records at a time. There is a facility to move to next or previous set of record or move forward or backwards by 1 record.
I have to find Min and Max of a column for the set of record currently visible. I am planning to use Compute method but I am not sure if it allows filtering on anything other than the columns in datatable.
Do I have to include row number in my query or is there a better solution (something along the line mentioned below)?
CType(dtLineup.Compute("Min(ArrivalDate)", dt.row(2) to dt.row(12)), Date)
There is nothing like your pseudo code in MSDN on DataColumn.Expression. You could include a row number in your query, as you said, but an alternative is to add a row number column to your data table and use that in the filter expression.
DataColumn col = new DataColumn("rownumber", typeof(int));
col.AutoIncrement = true;
col.AutoIncrementSeed = 1;
datatable.Columns.Add(col);
Another alternative could be to do paging by linq (Skip-Take) and compute the aggregate function over the returned rows. But that may be a major departure of your current application structure.