How can I make the system empty value from the guid null?-CodePudding

In the Build Query I have a query like this:

var characteristicPrices = await scope.BuildQuery<CharacteristicPrice, CharacteristicVersion, CharacteristicPrice>((op, ccp, cv) => op.Select(op.AllColumnsOf(ccp))
   .InnerJoin<CharacteristicVersion>(cv.Id == ccp.CharacteristicVersionId)
   .Where(ccp.CountryId == request.CountryId && cv.VersionId == request.VersionId)).Get();

Here the request.CountryId field comes to me as "000000...". but my query is not working correctly because its equivalent is null in the database. How can I set this value to null?

CodePudding user response：

You can either directly pass null to the query instead of Guid.Empty or you could modify your condition:

Either...

Guid? id = request.CountryId;
if (id==Guid.Empty) 
{ 
  id = null; 
}
var characteristicPrices = await scope.BuildQuery<CharacteristicPrice, CharacteristicVersion, CharacteristicPrice>((op, ccp, cv) => op.Select(op.AllColumnsOf(ccp))
   .InnerJoin<CharacteristicVersion>(cv.Id == ccp.CharacteristicVersionId)
   .Where(ccp.CountryId == id && cv.VersionId == request.VersionId)).Get();

...or...

var characteristicPrices = await scope.BuildQuery<CharacteristicPrice, CharacteristicVersion, CharacteristicPrice>((op, ccp, cv) => op.Select(op.AllColumnsOf(ccp))
   .InnerJoin<CharacteristicVersion>(cv.Id == ccp.CharacteristicVersionId)
   .Where((ccp.CountryId == request.CountryId || (request.CountryId==Guid.Empty && ccp.CountryId=null)) && cv.VersionId == request.VersionId)).Get();