Write Net Code (condition) in SQL Server

I want to convert this below vb.net code to sql code. can you help please?

If ArticleItems.Count = 1 _
AndAlso ((ArticleItem.SerialNumber = ArticleItems(0).SerialNumber And Not String.IsNullOrEmpty(ArticleItem.SerialNumber) And ArticleItem.IMEI <> ArticleItems(0).IMEI) _
Or (ArticleItem.SerialNumber <> ArticleItems(0).SerialNumber And ArticleItem.IMEI = ArticleItems(0).IMEI And Not String.IsNullOrEmpty(ArticleItem.IMEI))) Then

ReturnMessage = sp.ArticleItemUpdate(Login, ArticleItem, "SERIMEI")