DataSource Controls :: Number 1 Working As The Same As Number 2?

any one know why are the following two give me different result? they should both give me no results as the value I give is not available. however, number 1 give me many results, and number 2 works as expected. I'd like the number 1 working as the same as number 2.

1. DECLARE

@SearchMCat nvarchar,
@SearchTitle nvarchar,
@SearchDesc nvarchar
SET @SearchMCat = 'fjiewo;jafoia'
SET @SearchTitle = 'fryere'
SET @SearchDesc = 'fdsfdsafae33'
SELECT ArticleCategory.CategoryDisplayName, Article.AudioPlaybackTargetTabID, Article.VideoPlaybackTargetTabID, Article.StartTime, Article.DateAdded, Article.Body, Article.Synopsis, Article.Title, Article.ArticleHasAudio, Article.ArticleHasVideo, Article.createdBy,
Article.RatingTotal, Article.RatingCount, Article.ArticleID, ArticleCategory.CategoryName
FROM ArticleCategory RIGHT OUTER JOIN Article ON ArticleCategory.ArticleCategoryID = Article.MasterCategory
WHERE (ArticleCategory.CategoryName LIKE '%' + @SearchMCat + '%') or (Article.Title LIKE '%' + @SearchTitle + '%') or (Article.Body LIKE '%' + @SearchDesc + '%')

2.

SELECT ArticleCategory.CategoryDisplayName, Article.AudioPlaybackTargetTabID, Article.VideoPlaybackTargetTabID, Article.StartTime, Article.DateAdded, Article.Body, Article.Synopsis, Article.Title, Article.ArticleHasAudio, Article.ArticleHasVideo, Article.createdBy, Article.RatingTotal, Article.RatingCount, Article.ArticleID, ArticleCategory.CategoryName
FROM ArticleCategory RIGHT OUTER JOIN Article ON ArticleCategory.ArticleCategoryID = Article.MasterCategory
WHERE (ArticleCategory.CategoryName LIKE '%' + 'fdsafdsafdsa' + '%') or (Article.Title LIKE '%' + 'fffaery' + '%') or (Article.Body LIKE '%' + 'fdas3r43ffdsa' + '%')