How to Group Data by Multiple Columns in LINQ?

LINQ multiple groups of groups in detail

In SQL, you can use

clauses to group data based on multiple columns. For example:

GROUP BY

How to implement similar functions in Linq?

<code class="language-sql">SELECT * FROM <tablename> GROUP BY <column1>,<column2></code>

Use anonymous type

One method is to use anonymous type. The following is an example:

This code is grouped based on the

and

<code class="language-csharp">var groupedData = x.GroupBy(x => new { x.Column1, x.Column2 });</code>

attributes of the elements in the

sequence to create an anonymous type for each unique combination of value. x Column1 Data example Column2

Consider the following data structure:

and the following INSERT statement:

<code class="language-csharp">public class QuantityBreakdown
{
    public int MaterialID { get; set; }
    public int ProductID { get; set; }
    public float Quantity { get; set; }
}</code>

You can use the following code to convert this to linq:

<code class="language-sql">INSERT INTO @QuantityBreakdown (MaterialID, ProductID, Quantity)
SELECT MaterialID, ProductID, SUM(Quantity)
FROM @Transactions
GROUP BY MaterialID, ProductID</code>

This linq expression is paid according to

and

, and then calculates the sum of the

<code class="language-csharp">var groupedTransactions = transactions
    .GroupBy(t => new { t.MaterialID, t.ProductID })
    .Select(g => new QuantityBreakdown
    {
        MaterialID = g.Key.MaterialID,
        ProductID = g.Key.ProductID,
        Quantity = g.Sum(t => t.Quantity)
    });</code>

value of each group.

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