LINQ in C# (SQL vs LINQ)

linq-in-c#

LINQ in C#

        It represents Language Integrated Query. It is a query language design by Microsoft using which we can write queries on a different verity of data sources to retrieve data form data source , like data from Array and collections.

 Basically it is derived from the SQL where SQL used in RDBMS and LINQ is use in programming language like c#.When we going to use LINQ in programming first of all we should import the system.Linq from library.

LINQ program example

Write a program to display the numbers greater than 40 from the array using LINQ statement.

using Systme;

using System.Linq ;

 Staic void Main()

{

   int[] arr = { 23, 34, 43,41, 54, 15, 4, 0, 66, 72, 91, 45, 17,86};

   var brr = from i in arr where i>40 orderby i select i;

   foreach (int a in brr)

      Console.Write({“0}\t”,a);

   Conosole.ReadLine();

}

Difference between SQL and LINQ

SQL	LINQ
Ø  SQL is a Structure Query Language use in RDBMS (Relational Data Base Management System) mainly in Sql Workbench.    Ø  SQL is used in Relational Data Base to retrieve and Manuplication of data from Tables or Relations.    Ø  The syntax of SQL start from ‘Select ‘clause and end with clauses like (where, group by, having and orderby).    Ø  Syntax Select [<columns>] From [<Table>]  [<Clauses>] Note : Clauses contain Where, Groupby, Having and Orderby . clauses are optional and it always in the above sequence.	Ø  LINQ is a Language Integrated Query use by programmer in programming language, like in c#.     Ø  LINQ is used in programming to retrieve data form Array and Collection.     Ø  The syntax starts with ‘From’ clause and end with ‘Select’ clause.     Ø  Syntax from [<alias>] in <collection | array> [<Clauses>] Select[<alias>] here all the place of columns name we going to use alias. Alias in nothing it just a name like ‘I’, ‘a’ whatever you want names it.
Example difference	Example difference
Suppose we have a table ‘Num’ contain only one column ‘col1’ and it contain the following data 23, 34, 43,41, 54, 15, 4, 0, 66, 72, 91, 45, 17,86	Suppose we have an array ‘arr’ contain the following data same as in table 23, 34, 43,41, 54, 15, 4, 0, 66, 72, 91, 45, 17,86
List col1 greater than 40 Select col1 From Num Where col1> 40 orderby col1;	print array greater than 40 from i in arr where i>40 orderby i select i;