Anthony D. Weiner garners the support of 10 percent of Democratic voters, confirming his slippage in the race that other surveys have also recorded since revelations that he continued to have sexually explicit exchanges with women online after he resigned from Congress two years ago. The remaining candidates in the poll each drew less than 5 percent; 26 percent of the Democratic voters surveyed were undecided.
Among Democrats who say they will definitely vote in the primary, Ms. Quinn is backed by 26 percent, followed by 19 percent for Mr. Thompson and 14 percent for Mr. de Blasio. A runoff will be held on Oct. 1 if none of the candidates win support from at least 40 percent.
Ms. Quinn far outpaces her rivals in Manhattan, where she is backed by a third of Democratic voters. And she is supported by nearly 4 in 10 voters with household incomes of $100,000 or more.