查找平均 ID，然后从另一个表中获取具有相同 ID 的数据

Question

我需要在客户端表中找到平均 grid_id，然后从具有相应 id 的网格表中获取 x 和 y。 我在这里试过这个查询：

SELECT round(AVG(client_id)) as testyy, grid.x,grid.y 
FROM client
JOIN grid
ON client.grid_id = grid.grid_id
WHERE grid.grid_id = AVG(client_id)
group by GRID.X,GRID.Y

但似乎无法让它工作。

DESIRED OUTPUT：平均网格位置

示例数据：网格表

INSERT INTO grid (x,y) values (-10,-10);
INSERT INTO grid (x,y) values (-10,-9);
INSERT INTO grid (x,y) values (-10,-8);
INSERT INTO grid (x,y) values (-10,-7);
INSERT INTO grid (x,y) values (-10,-6);
INSERT INTO grid (x,y) values (-10,-5);
INSERT INTO grid (x,y) values (-10,-4);

示例数据：客户表

INSERT INTO client (name,payment_method,grid_id,service_id) VALUES ('Derri','cash',563,57);
INSERT INTO client (name,payment_method,grid_id,service_id) VALUES ('Eil','card',616,758);
INSERT INTO client (name,payment_method,grid_id,service_id) VALUES ('Sid','cash',595,59);
INSERT INTO client (name,payment_method,grid_id,service_id) VALUES ('Amelia','card',601,60);
INSERT INTO client (name,payment_method,grid_id,service_id) VALUES ('Lewis','card',479,61);
INSERT INTO client (name,payment_method,grid_id,service_id) VALUES ('Mel','card',480,62);
INSERT INTO client (name,payment_method,grid_id,service_id) VALUES ('Gordon','card',480,63);
INSERT INTO client (name,payment_method,grid_id,service_id) VALUES ('Gino','card',479,64);

Answer 1

查找平均 ID，然后从另一个表中获取具有相同 ID 的数据

也许子查询可以解决问题。 尝试：

select x, y
from grid
where id = ( 
  select round( avg( grid_id ) )
  from client 
) ;