创建表作为select是在postgresql中删除非空约束

SELECT conname, relname, nspname
FROM pg_constraint c
JOIN pg_class t ON t.oid = c.conrelid
JOIN pg_namespace n ON n.oid = t.relnamespace
WHERE contype = 'c' AND nspname = 'public' AND relname = 'your_table_name';

ALTER TABLE your_table_name DROP CONSTRAINT your_constraint_name;

CREATE TABLE new_table_name AS
SELECT * FROM your_table_name WHERE your_column_name IS NOT NULL;

DROP TABLE your_table_name;

ALTER TABLE new_table_name RENAME TO your_table_name;