Another heavy-hitting union has picked a candidate in the crowded Democratic field for state Attorney General.

The Retail, Wholesale and Department Store Union this morning endorsed Nassau District Attorney Kathleen Rice, who is competing against five others in the primary.

“I am not an insider from Albany. I am not a career Albany politician. I am not a Wall Street insider. I am a career prosecutor,” Rice said outside City Hall upon receiving the endorsement.

The candidates are expecting the seat to become open if AG Andrew Cuomo runs for governor, as is widely expected.

When asked about controversial plans for Wal-Mart to build a store in New York, Rice said she “stands with working families,” but would not commit to opposing the mega-store building a branch in the city.

RWDSU President Stuart Applebaum spoke vehemently against Wal-Mart.