That's a good thing: it gives you great leverage to ensure good retention-pay.
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During your 1:1s/"connects"/perf-evals, don't frame it as "I hate being the only one here who knows SQL, I'm quitting/gimmie-a-raise", instead frame it as "I'm proud of the great accomplishments that my unique and deep understanding of both database-theory and SQL in-practice have brought to the company; given my significant responsibilities I now have in the team/company I'm sure you'll "recognize" my now quite-significant leading-role...."
(for best effect make the "money-gesture" with your fingers during the last part).
...I wish I had the gall to do that when I was younger.