Clojure, merging two array of maps

I have two arrays of maps

1st is [{:a 1 :b 2 :d 6} {:a 2 :b 2} {:a 7 :b 7}]

2nd is [{:a 3 :c 3 :e 9 :y 7} {:a 2 :b 6 :c 8}]

depending on the value of a i.e. if its matches in 2nd array the '2nd map' should be merged with '1st map' and the resultant array of maps should be

Res should be [{:a 1 :b 2 :d 6} {:a 2 :b 6 :c 8} {:a 7 :b 7} {:a 3 :c 3 :e 9 :y 7}]

Can anyone help me on this. Thanks in advance.

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