Is it possible to make a simple query to count how many records I have in a determined period of time like a year, month, or day, having a TIMESTAMP field, like: SELECT COUNT(id) FROM stats WHERE record_date.YEAR = 2009 GROUP BY record_date.YEAR Or even: SELECT COUNT(id) FROM stats GROUP BY record_date.YEAR, record_date.MONTH To have … Read more
What is the most efficient way to groupby objects in an array? For example, given this array of objects: [ { Phase: “Phase 1”, Step: “Step 1”, Task: “Task 1”, Value: “5” }, { Phase: “Phase 1”, Step: “Step 1”, Task: “Task 2”, Value: “10” }, { Phase: “Phase 1”, Step: “Step 2”, Task: “Task … Read more
How can I do GroupBy multiple columns in LINQ Something similar to this in SQL: SELECT * FROM <TableName> GROUP BY <Column1>,<Column2> How can I convert this to LINQ: QuantityBreakdown ( MaterialID int, ProductID int, Quantity float ) INSERT INTO @QuantityBreakdown (MaterialID, ProductID, Quantity) SELECT MaterialID, ProductID, SUM(Quantity) FROM @Transactions GROUP BY MaterialID, ProductID 14 … Read more
There is a table messages that contains data as shown below: Id Name Other_Columns ————————- 1 A A_data_1 2 A A_data_2 3 A A_data_3 4 B B_data_1 5 B B_data_2 6 C C_data_1 If I run a query select * from messages group by name, I will get the result as: 1 A A_data_1 4 … Read more
Let’s suppose if we have a class like: class Person { internal int PersonID; internal string car; } I have a list of this class: List<Person> persons; And this list can have multiple instances with same PersonIDs, for example: persons[0] = new Person { PersonID = 1, car = “Ferrari” }; persons[1] = new Person … Read more
I understand the point of GROUP BY x. But how does GROUP BY x, y work, and what does it mean? 3 Group By X means put all those with the same value for X in the one group. Group By X, Y means put all those with the same values for both X and … Read more
As the title suggests, I’d like to select the first row of each set of rows grouped with a GROUP BY. Specifically, if I’ve got a purchases table that looks like this: SELECT * FROM purchases; My Output: id customer total 1 Joe 5 2 Sally 3 3 Joe 2 4 Sally 1 I’d like … Read more