Through the 2009 season, that is John Olerud at .315. Olerud played for the Mets between 1997-1999 and had 524 base hits in 1662 at bats for the team.
David Wright is second all time at .309.
Ty Cobb batted .367 for his career. That is the highest career batting average in major league baseball history.
Dave Magadan hit for .525 in 1983
John Olerud (1B) had a batting average of .354 in 1998 which is the current record. John Olerud also holds the record of best career Met batting average with a .315.
Josh Hamilton his record is a .361 hitting average. Don Bradman has the highest in tests with an average of 99.94
Hall of Famer Ty Cobb has Major League Baseball's highest career average. The official number is .367, though statisticians later found a mistake in the totals, and his actual career average is .366 (still the record).
The record for the highest single season batting average is held by Hugh Duffy, who batted .440 in 1894.
If you mean in a career, nobody has remotely approached it. His .366 LIFETIME batting average has been bested for ONE YEAR in either league only twelve times in the last fifty years. Cobb never held the record for highest batting average in a season. It was set by Hugh Duffy at .440 in 1894, and it is inconceivable to me that it will ever be broken.
Clemente hit .357 for the Pittsburgh Pirates in 1967, his highest batting average in any one season during his career. Incidently, the Pirates finished 6th in the 10 team National League that season with an 81-81 record.
Rogers Horsnby
John Olerud holds the record for highest batting average by a New York Met in a single season with .354 in 1998
Ted Williams had a career batting average of .344, 521 home runs and 1,839 RBIs
Barry Bonds holds the record with 762 career homeruns. He also has the most career walks with 2552. His career batting average was .298 but came at the cost of a $188,245,322 career salary.