A cable such as the Hosa STX-3xxM series, which has a 1/4-inch TRS phone plug on one end and a 3-pin male XLR plug on the other end, should do the job nicely here. (The "xx" in the part number represents the cable length in feet... ie STX-310M is 10 feet long.) Hosa cables are widely available from various sources. Just do a Google search to find them.
I admit that I am really skittish about hanging long, heavy plug adapters on any sort of gear. The weight of a cable (or the force of someone bumping into it) translates into a lot of torque on the connectors. And breakage from stress on connectors is probably among the top 2 or 3 failure modes of gear.
The Hosa cable seems like a more prudent choice. I made one myself, but have not yet encountered a gig with full PA support.
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