MySQL 8.0

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CREATE TABLE temptbl (
  `left` JSON,
  `right` JSON
);

INSERT INTO temptbl
  (`left`, `right`)
VALUES
  ('[1, 2, 3, 4]', '["a", "ba"]'),
  ('[10, 20, 30, 40]', '["a", "ba"]');

Records: 2  Duplicates: 0  Warnings: 0


select group_concat(Distinct CONCAT("'",`left`,"'") SEPARATOR ',') INTO @sql
from temptbl where json_contains(`right` ,'"ba"','$') ;
SELECT CONCAT("SELECT JSON_MERGE( ",@sql,");") INTO @sql;
PREPARE stmt1 FROM @sql;
EXECUTE stmt1;
DEALLOCATE PREPARE stmt1;

Statement prepared




JSON_MERGE( '[1, 2, 3, 4]','[10, 20, 30, 40]')


[1, 2, 3, 4, 10, 20, 30, 40]