enter code hereI have two data tables one of the data tables connects to sql server and the other connects to oracle.
I am running query statements on both and those work perfectly find.
Now I need to write something that will compare the "UNIT_NO" in oracle to the "VehicleName" in sql. yes they are the same number.
Right now the Oracle table bring in 6 columns and the SQL brings in 4 columns
an example would be:
VehicleName, VehicleGroupName, UserDefinedColumn2, UserDefinedColumn3
Unit_No, Unit_ID, Using_Dept, Status, Using_Dept_Desc,
I want my code to find the matching number from Unit_NO and VehicleName and display all the above information all in one row. I was thinking linq but I cant get it to display correctly
This code combines the columns from both tables but pulls but does not add the any data in the rows any suggest or fixes
private void GetSQLOraclelinqData()
{
var TstarData = GetTrackstarTruckData();
var M5Data = GetM5Data();
DataTable ComTable = new DataTable();
foreach (DataColumn OraColumn in M5Data.Columns)
{
ComTable.Columns.Add(OraColumn.ColumnName, OraColumn.DataType);
}
foreach (DataColumn SQLColumn in TstarData.Columns)
{
if (SQLColumn.ColumnName == "VehicleName")
ComTable.Columns.Add(SQLColumn.ColumnName + 2, SQLColumn.DataType);
else
ComTable.Columns.Add(SQLColumn.ColumnName, SQLColumn.DataType);
}
var results = TstarData.AsEnumerable().Join(M5Data.AsEnumerable(),
a => a.Field<String>("VehicleName"),
b => b.Field<String>("Unit_NO"),
(a, b) =>
{
DataRow row = ComTable.NewRow();
row.ItemArray = a.ItemArray.Concat(b.ItemArray).ToArray();
ComTable.Rows.Add(row);
return row;
});
SQLDataTable.ItemsSource = ComTable.DefaultView;
}
I would do it using two nested for loops.
The outer for loop would iterate through each row in the SQL DataTable.
The inner loop would iterate through each row in the Oracle DataTable, and if there is a match, it would store the match somewhere (perhaps in a list).
Optional Hints
Assuming that each number plate only occurs once, we could optimise this code by breaking out of the inner loop as soon as we get a match.
We cannot rely on the rows coming back in the same order. Thus, we cannot naively compare row 1 from SQL against row 1 from Oracle.
my code is based off grabbing columns that are not populated yet in the datagrid I call two datatable on the code behind to populate the table and also us excel sheets. If anyone needs this information i can help.
I connect to SQL, Oracle and load excel sheets to make a comparison on data
Related
I'm working on an shopping website. User selects multiple filters on and sends the request to backend which is in node.js and using postgres as DB.
So I want to search the required data in a single query.
I have a json object containing all the filters that user selected. I want to use them in postgres query and return to user the obtained results.
I have a postgres Table that contains a few products.
name Category Price
------------------------------
LOTR Books 50
Harry Potter Books 30
Iphone13 Mobile 1000
SJ8 Cameras 200
I want to filter the table using n number of filters in a single query.
I have to make it work for multiple filters such as the ones mentioned below. So I don't have to write multiple queries for different filters.
{ category: 'Books', price: '50' }
{ category: 'Books' }
{category : ['Books', 'Mobiles']}
I can query the table using
SELECT * FROM products WHERE category='Books' AND 'price'='100'
SELECT * FROM products WHERE category='Books'
SELECT * FROM products WHERE category='Books' OR category='Mobiles'
respectively.
But I want to write my query in such a way that it populates the Keys and Values dynamically. So I may not have to write separate query for every filter.
I have obtained the key and value pairs from the request.query and saved them
const params = req.query;
const keys: string = Object.keys(params).join(",")
const values: string[] = Object.values(params)
const indices = Object.keys(params).map((obj, i) => {
return "$" + (i + 1)
})
But I'm unable to pass them in the query in a correct manner.
Does anybody have a suggestion for me? I'd highly appreciate any help.
Thank you in advance.
This is not the way you filter data from a SQL database table.
You need to use the NodeJS pg driver to connect to the database, then write a SQL query. I recommend prepared statements.
A query would look like:
SELECT * FROM my_table WHERE price < ...
At least based on your question, to me, it is unclear why would want to do these manipulations in JavaScript, nor what you want to be accomplished really.
I am trying to figure out how to change 2 columns of data into one header row with multiple columns in Excel Power Query. It's my understanding that Query keeps the Excel file size small, and is less on the processes, as opposed to using tons of vlookups or pivot tables. I'm open to VBA if that's a better option.
For example, I have Column A with a list of names. Then, column B has another list of names with multiple instances of the same name(s). The names in column A are individuals assigned to report to individuals in B.
I'm trying to create a query (or VBA if better) where the names in B become the row headers, and the names in A fall under the corresponding person in each header.
I hope that makes sense. Thank you in advance for your help!
Here's a screenshot, demonstrating what I'm working with, and the end result I'm trying to get:
You can use Power Query:
let
Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
ListEmployees = Table.Group(Source, {"Supervisor Name"}, {{"Employees", each Text.Combine([Employee Name],","), type text}}),
CountEmployees = Table.AddColumn(ListEmployees, "Count", each List.Count(Text.Split([Employees],","))),
SplitEmployees = Table.SplitColumn(ListEmployees, "Employees", Splitter.SplitTextByDelimiter(",", QuoteStyle.Csv),List.Max(CountEmployees[Count])),
Transpose = Table.Transpose(SplitEmployees),
PromoteHeaders = Table.PromoteHeaders(Transpose, [PromoteAllScalars=true])
in
PromoteHeaders
Make sure your source data is structured as a Table (listobject).
I have two queries, first query return top 10/20 recoords, second query return total record count from first query. Both queries need to use same filter condition.
How can I write filter condition and parameter used in filter condition in one place and use in both the queries.
Condition I can store in string variable and use in both the queries but how to share parameters?
I am using HQL
Check this similar Q & A: Nhibernate migrate ICriteria to QueryOver
There is a native support in NHiberante for row count. Let's have some query
// the QueryOver
var query = session.QueryOver<MyEntity>();
It could have any amount of where parts, projections... Now we just take its underlying criteria and use a transformer to create brand new criteria - out-of-box ready to get total rowcount
// GET A ROW COUNT query (ICriteria)
var rowCount = CriteriaTransformer.TransformToRowCount(query.UnderlyingCriteria);
Next step is to use FUTURE to get both queries in one round trip to DB
// ask for a list, but with a Future, to combine both in one SQL statement
var list = query
.Future<MyEntity>()
.ToList();
// execute the main and count query at once
var count = rowCount
.FutureValue<int>()
.Value;
// list is now in memory, ready to be used
var list = futureList
.ToList();
I have a table with more than 2 columns (let's say A, B and C). One column holds some numbers (C) and I want to do a "group by" like grouping, summing the numbers in C, but I don't know the algorithm for doing so.
I tried sorting the table by each column (from last to first, aside from the numbers column (C), so in this case: sort(B) and then sort(A)) and then, wherever nth row holds same values in A and B as in n-1th row, I add the number from nth row to n-1th row (in the C column), and then delete the nth row. Else, if A or B value in row n differs from A or B value in n-1th row, I'll just move to the next row. Then I repeat the algorithm till the last row in table. But somehow this isn't working all the time, especially when there're a lot more columns (some rows remain ungrouped, maybe because of the sorting method).
I want to know whether this is a good grouping algorithm and I need to look for the problem into the sorting method, or I need to use another (sorting and/or grouping) algorithm and which one. Thank you.
LE: Apparently the algorithm that I used works well after a thorough check of the code and fixing some minor mistakes that junior programmers like me often make :)
I think a good way to do this would be to wrap your row into a class, implement the equals method, and then use a Map to add the values up:
public class MyRow {
private Long columnA;
private String columnB;
private int columnC;
#Override
public boolean equals(final Object other) {
if (!other instanceof MyRow) {
return false;
}
final MyRow otherRow = (MyRow) other;
return this.columnA.equals(otherRow.getColumnA()) && this.columnB.equals(otherRow.getColumnB);
}
}
Then you can iterate over all the rows, and create a Map for holding the sums of C.
final Map<MyRow, Integer> computedCSums = new HashMap<MyRow, Integer>();
for (final MyRow myRow : myRows) {
if (computedCSums.get(myRow) == null) {
computedCSums.put(myRow, myRow.getColumnC());
} else {
computedCSums.put(myRow, computedSums.get(myRow) + myRow.getColumnC());
}
}
Then, to get the sum of grouped Cs of any row, you just do:
computedCSum.get(mySelectedRow);
I think there is three things should be considered about group by
less or equal is abstract
comparing two rows A, B according it columns (C1..Cn) are like this : compare each column from C1 to Cn , if we can get which is less, then return ,or if the two values are equal, then we go to compare next, repeat this until return.
which algorithm we choose
1)build a binary search tree or a hash table to store tuples , when we get a tuple, search the equal tuple , if we have , then merge the tuple which have the same group value, else put it to our search structure
2) read some tuples, then sort , walk the buffer and merge the same group
I prefer 1 rather than 2.
memory size
if out input is huge, we must consider memory limit.
we can use merge algorithm to deal this.
if memory exceed our limit , then write the tuples in memory to the tape order by their group columns
when we finish reading the input, then merge the result set in tape.
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.