LINQ uses GROUP by 1

LINQ uses GROUP by 1

1. Simple form:

1. var q =
2. from P in Db. Products
3. Group p by P.categoryid into G
4. Select G;

Statement Description: LINQ uses Group by to divide products by CategoryID.

Description: from P in db. Products means that the product objects are taken out of the table. Group p by P.categoryid into G indicates that P is categorized by the CategoryID field. The result is named G, and once renamed, the scope of P is ended, so the last select can only select G.

2. Maximum Value

1. var q =
2. from P in Db. Products
3. Group p by P.categoryid into G
4. Select New {
5. G.key,
6. Maxprice = g.max (p => p.unitprice)
7. };

Statement Description: LINQ uses GROUP by and Max to find the highest unit price per CategoryID.

Description: First according to CategoryID classification, judging the price of the largest products in each category. Remove the CategoryID value and assign the UnitPrice value to Maxprice.

3. Minimum value

1. var q =
2. from P in Db. Products
3. Group p by P.categoryid into G
4. Select New {
5. G.key,
6. Minprice = g.min (p => p.unitprice)
7. };

Statement Description: LINQ uses Group by and Min to find the lowest unit price per CategoryID.

Description: First, according to CategoryID classification, judging the lowest unit price of products in each category. Remove the CategoryID value and assign the UnitPrice value to Minprice.

4. Average

1. var q =
2. from P in Db. Products
3. Group p by P.categoryid into G
4. Select New {
5. G.key,
6. Averageprice = G.average (p => p.unitprice)
7. };

Statement Description: LINQ uses Group by and average to get the average unit price per CategoryID.

Description: First by CategoryID classification, remove the CategoryID value and the average price of each product category.

5. Summation

1. var q =
2. from P in Db. Products
3. Group p by P.categoryid into G
4. Select New {
5. G.key,
6. Totalprice = g.sum (p => P.unitprice)
7. };

LINQ uses GROUP by 1