-- MySQL 8.0+; target database: baiyue_lastleg.
-- Re-runnable: allow pallet-less carton outbound records.
SET NAMES utf8mb4;
USE baiyue_lastleg;

SET @ddl = (SELECT IF(EXISTS (
  SELECT 1 FROM information_schema.columns
  WHERE table_schema=DATABASE() AND table_name='ll_outbound_pallet_item'
    AND column_name='pallet_no' AND is_nullable='NO'
), 'ALTER TABLE ll_outbound_pallet_item MODIFY COLUMN pallet_no VARCHAR(128) NULL COMMENT ''托盘号，箱维度出库为空''', 'SELECT 1'));
PREPARE stmt FROM @ddl; EXECUTE stmt; DEALLOCATE PREPARE stmt;

SELECT DATABASE() AS target_database, table_name, column_name, is_nullable
FROM information_schema.columns
WHERE table_schema=DATABASE() AND table_name='ll_outbound_pallet_item' AND column_name='pallet_no';