MariaDB 10.3

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CREATE TABLE privileges (
    id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
    label VARCHAR(25)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO privileges (label) VALUES ('item1');
SELECT * FROM privileges;


id
label


1
item1


INSERT INTO privileges (label)
SELECT label
FROM (
 SELECT 'item1' as label UNION ALL 
 SELECT 'item2'
) i
WHERE NOT EXISTS (SELECT 1 FROM privileges p WHERE p.label = i.label);
SELECT * FROM privileges;


id
label


1
item1

2
item2