SQLite 3.27

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CREATE TABLE Table1 (
  `id` INTEGER PRIMARY KEY, 
  `value1` TEXT, 
  `ids` TEXT, 
  `value2` TEXT
);
✓
INSERT INTO Table1 (`id`, `value1`, `ids`, `value2`) VALUES
  ('1', 'abcd', '1,2,3', 'efgh'),
  ('2', 'ijkl', '1,4,6', 'mnop');
✓
CREATE TABLE Table2 (`id` INTEGER, `name` TEXT);
✓
INSERT INTO Table2 (`id`, `name`) VALUES
  ('1', '1AB'),
  ('2', '2CD'),
  ('3', '3EF'),
  ('4', '4GH'),
  ('5', '5IJ'),
  ('6', '6KL');
✓
SELECT t1.*,  
       GROUP_CONCAT(t2.name, '/') groupedName
FROM table1 t1 LEFT JOIN table2 t2 
ON ',' || t1.ids || ',' LIKE '%,' || t2.id || ',%'
GROUP BY t1.id;


id
value1
ids
value2
groupedName


1
abcd
1,2,3
efgh
1AB/2CD/3EF

2
ijkl
1,4,6
mnop
1AB/4GH/6KL