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CREATE TABLE tablename (id INTEGER PRIMARY KEY, columnname nvarchar(30));
INSERT INTO tablename VALUES
(1, 'abcdefghijk'), (2, 'xyz');
2 rows affected
UPDATE tablename SET columnname = LEFT(columnname, 5);
2 rows affected
ALTER TABLE tablename ALTER COLUMN columnname nvarchar(5);
SELECT * FROM tablename;
| id | columnname |
|---|---|
| 1 | abcde |
| 2 | xyz |