Answer by taking a quote from the following article:

Andrew Baines Bernard (born in 1973; Walter Bernard, Jr.) is a fictional character from the U.S. comedy television series, The Office. Andy is portrayed by Ed Helms. He has no counterpart in the original British version of the series. He is introduced as the Regional Director in Charge of Sales at the Stamford branch of paper distribution company Dunder Mifflin in the third-season premiere when Jim Halpert transfers, ultimately merging with the Scranton branch in the episode "The Merger" later in the season.

With the departure of Karen after Jim dumping her off-screen, Andy becomes the only salesman from Stamford aside from Jim to stay on at the Scranton branch. A preview clip for the fourth season features Andy taking up inner-tubing. The fourth-season premiere, "Fun Run", has Andy competitively participating in Michael's superfluously named run for rabies prevention through strategically drafting Kevin, although he falls prey to "nipple chafing."  Andy develops a friendship with Dwight in the second episode "Launch Party", in which he supports Dwight in beating the online sales of the company website Dunder Mifflin Infinity using a bear horn, much to the irritation of the office. He also develops a relationship with Angela, not being aware of Dwight and Angela's previous romantic interludes. He steals an elaborate ice sculpture for Angela's launch party, and serenades her later in the same episode with a rendition of the ABBA song "Take a Chance on Me", receiving a rare, yet quickly suppressed smile in return. He moonwalks in "Money" by her desk to impress her, although it takes the gift of the cat Garbage (from the previous episode) and a sentimental note to finally win her. Angela and Andy continue to date into "Local Ad", in which Andy consults Dwight on how to pursue more intimacy with Angela. Andy discusses the exclamation of "Oh, D!" Angela exclaims during intimate moments, unaware that Angela may be referring to a nickname for Dwight and not him.  Andy and Kevin successfully team up in the season to recover lost parking spaces taken by renovators of another company in the business park in a meeting of the building tenants, called "The Five Families". He is rebuffed from clubbing in "Night Out" with Michael and Dwight in New York with the newly promoted Ryan by Dwight, who has a rekindled dislike for Andy considering his relationship with Angela. This is evidenced later in "Did I Stutter?" when Dwight uses pressuring negotiation tactics in order to buy Andy's Nissan Xterra at a reduced price, only to flip it for profit on eBay much to Andy's protest.  In "Job Fair", Andy is invited to accompany Jim on a major sales call. However, in a deleted scene, Jim reveals Andy was invited in order to benefit Jim, as Andy's pride for Cornell would push the client- a graduate of Dartmouth- toward him. The scheme plays out as intended when the client invites Kevin to play golf with him again but denies Andy's request to join them.  In "Goodbye, Toby", Andy proposes to Angela (unbeknownst to him, at the same moment Jim had been preparing to propose to Pam) with a ring that he has carried in his wallet for six years, because "You never know when you'll meet the right girl". Angela accepts his proposal with a somewhat irritated "Okay"; shortly thereafter, though, she rekindled her intimate relationship with her former lover, Dwight, which is witnessed by Phyllis and the camera crew, who walk in on them making love by her desk.

Does he have any rivalries with Dwight?
Dwight uses pressuring negotiation tactics in order to buy Andy's Nissan Xterra at a reduced price, only to flip it for profit on eBay much to Andy's protest.