-- Emergency collation alignment for aihr_practice_assignment.
-- Root cause: production database uses utf8mb4_general_ci for tenant_id column
-- (inherited from RuoYi base schema), but ext_party_id column lacks explicit
-- COLLATE clause and inherits utf8mb4_0900_ai_ci from the table DEFAULT.
-- When the subquery JOIN in AihrPracticeSeedService.assignments() compares
-- aihr_practice_assignment.ext_party_id = aihr_practice_question_feedback.ext_party_id,
-- MySQL rejects the implicit collation coercion with error 1267.
--
-- Fix: align ext_party_id column collation with the canonical tenant_id collation
-- already in use by the target database (utf8mb4_general_ci in production).

SET @assignments_target_collation := (
  SELECT collation_name
    FROM information_schema.columns
   WHERE table_schema = DATABASE()
     AND table_name = 'aihr_practice_assignment'
     AND column_name = 'tenant_id'
   LIMIT 1
);
SET @assignments_target_collation := COALESCE(@assignments_target_collation, 'utf8mb4_0900_ai_ci');

SET @assignments_ddl := CONCAT(
  'ALTER TABLE `aihr_practice_assignment` MODIFY COLUMN `ext_party_id` varchar(100) COLLATE ',
  @assignments_target_collation,
  ' NOT NULL COMMENT ''员工外部主体或手机号'''
);
PREPARE assignments_stmt FROM @assignments_ddl;
EXECUTE assignments_stmt;
DEALLOCATE PREPARE assignments_stmt;

SET @assignments_ddl := NULL;
SET @assignments_target_collation := NULL;