CODEWITHSUNDEEP
c#entity-frameworklambda
bansi
bansi

Reputation: 99

Lambda expression to get records that matches to list of data

I have 

string[] centersArr = new string[] {253, 6789, 9080};

I want to query database where center number start with any of the items of above centers array and the 8th character of center should be '1'.

var result = disctrict.Where(x => centersArr.Contains(x.Center) && x.Center[7] == '1').ToList();

My database has center numbers like 2533455, 2537890, 25312678, 678912 and so on..

Above query is returning null result. Please help me how to write this query.

Upvotes: 1

Views: 2434

Answers (2)

bansi
bansi

Reputation: 99

i solved this:

.Where(x => centersArr.Any(c => x.Center.StartsWith(c)) && ....)

Upvotes: 1

DWright
DWright

Reputation: 9500

centersArr.Contains(x.Center) is not going to work.

The items in centersArr genuinely cannot contain any of the example database values that you give. And I suspect that's true for all of your database values.

In essence you are asking for a situation where the following is true (the following is super pseudo pseudocode) 

ListOfCenters('A','B','C').Contains(ListOfLongerItemsFromDatabase('WORDA', 'BWORD', 'WORDC').

That's exactly backward. WORDA or BWORD or WORDC can and do contain A,B, or C. But not the reverse.

Does that help clarify?

This, however, should work:

var result = disctrict.Where(x => (x.Center.Contains("253") || x.Center.Contains("6789") || x.Center.Contains("9080")) && x.Center[7] == '1').ToList();

unless Linq to SQL cannot translate that into a SQL expression . . .. If it doesn't work, at least it shows conceptually what you really want to be doing instead.

Upvotes: 0

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