如何在Linq中使用OR运算符

Question

I want to use OR function in my linq query. Ex: Sql:

select * from tblusers where userid=1 and status='a' or status='b';

Linq:

var result= _Repository.selectAll().where(x=>x.UserID==1 && x.status=="a" OR x.status=="B");

It's does work for linq query. so does anyone have any idea?

Answer 1

So you are aware about the && operator for comparison, then why not make a try with || operator? Anyway here is the solution for your problem, Following code will get you the result with UserID is 1 and status is either a or B .

 _Repository.selectAll().where(x=>x.UserID==1 && (x.status=="a" || x.status=="B"));

Answer 2

Create an array of status you want to check and then use contains . something like this.

var statusList = new[] {"a", "b"};

.Where(x=> x.UserID == 1 &&  statusList.Contains(x.status));

Answer 3

Adding my 2 cents in here, there is another way you can write your sql query in C# which more or less resembles the sql syntax.

var result = from x in _Repository.SelectAll() where x.UserID == 1 && (x.Status == "a" || x.Status == "B") select x;

This syntax is Query Syntax/Expression where as your snippet is Method Syntax/Expression . Both will achieve same results. Also behind the scene, query syntax is compiled to Method syntax.

At compile time, query expressions are converted to Standard Query Operator method calls according to the rules set forth in the C# specification. Any query that can be expressed by using query syntax can also be expressed by using method syntax. However, in most cases query syntax is more readable and concise.

Answer 4

Or other approach with List.Contains , which generates sql query like
SELECT * FROM tblusers WHERE userid=1 AND status IN ('a','b');

var acceptedStatus = new List<string> { 'a', 'b' };
var result= _Repository.selectAll()
                       .Where(x => x.UserID == 1)
                       .Where(x => acceptedStatus.Contains(x.Status));

Notice that instead of && operator you can use another Where function and chain them. Can be more readable then fit all conditions in one line.

Answer 5

Try code:

var result =( from  x in _Repository.selectAll()
           where x.UserID==1 && (x.status=="a" || x.status=="B") select x);

another Solution

 var result =( from  x in _Repository.selectAll().where(c=>c.status=="a" || x.status=="B")
               where x.UserID==1  select x);