Historical U.S. Comparisons support the claim: solar employment exceeded direct coal-mining employment in documented periods, including 2016. However, the statement omits the comparison year and treats different employment measures as interchangeable, since the solar figures cover installation or the broader solar industry while the coal figures generally cover direct mining jobs.
The United States has more people employed in solar energy than in coal mining.

US solar industry now employs more workers than oil and gas, says report | Energy industry | The Guardian
Source: theguardian.com
Key Evidence
The Guardian reported that U.S. Solar installation employment exceeded domestic coal-mining employment by 77 workers in the reported comparison period.
PolitiFact cited 260,077 U.S. Solar workers in 2016 versus approximately 87,000 U.S. Coal-mining workers.
The New York Times reported that the U.S. Solar industry employed many more Americans than coal in the prior year it examined, corroborating the historical comparison.
What the Evidence Shows
The central comparison is supported for specific historical periods. The Guardian reported that the U.S. Solar installation sector employed 77 more people than domestic coal mining, while PolitiFact cited 260,077 U.S. Solar workers in 2016 compared with approximately 87,000 coal-mining workers. The New York Times also reported that the solar industry employed many more Americans than coal in the referenced prior year.
The supporting employment measures are defined, but they are not identical. Solar counts range from installation employment to broader solar-industry or Solar Jobs Census categories. The Solar Jobs Census figure cited by PolitiFact counted 142,698 Americans employed in the solar industry in November 2013. The coal comparison generally refers to direct coal-mining employment, rather than all jobs connected to the coal sector.
Thus, the evidence supports the direction of the comparison for documented historical years and specified measures. It does not show that solar employment exceeded coal-mining employment in every period or under every possible definition, and it does not establish the claim's current status without a date.