下面的命令获取给定数据库模式中的所有外键查询，但它也响应一些重复的外键，所以请告诉我，有人，如何克服这个问题，并请给出一个独特选项的示例。

SELECT SchemaName, GROUP_CONCAT(DropQuery SEPARATOR ';\n') as DropQuery
  FROM
  (SELECT 
  KCU.REFERENCED_TABLE_SCHEMA as SchemaName,    
KCU.TABLE_NAME,
KCU.COLUMN_NAME,
CONCAT('ALTER TABLE ', KCU.TABLE_NAME, ' DROP FOREIGN KEY ', KCU.CONSTRAINT_NAME) AS DropQuery 
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE KCU, information_schema.REFERENTIAL_CONSTRAINTS RC
WHERE
KCU.CONSTRAINT_NAME = RC.CONSTRAINT_NAME
AND KCU.REFERENCED_TABLE_SCHEMA = RC.UNIQUE_CONSTRAINT_SCHEMA
AND KCU.REFERENCED_TABLE_SCHEMA = 'jtrac') Queries
GROUP BY SchemaName;