使用IN-运算符作为变量使用MySQL查询的结果。

Question

寻找一种返回可以在IN-operator中使用的变量的方法。

我当前的结果返回：1,2,3，但我想变量应该更像这样：'1','2','3'才能使用它。

这个是可能的吗？

或者我应该尝试一些其他的东西，比如爆炸，保存查询，.

-- init vars
SET @export_date = '2022-06-20'; 
SET @order_ids = ''; 

-- Tasks on given day
SELECT * FROM tasks WHERE task_execution_date = @export_date;

-- method 1
SET @order_ids = (SELECT GROUP_CONCAT(DISTINCT task_order SEPARATOR ',' )  FROM tasks WHERE task_execution_date = @export_date); 
SELECT @order_ids; -- "1,2,3"

-- method 2
SET @order_ids = (SELECT GROUP_CONCAT(DISTINCT '' + cast( task_order  AS CHAR(50)) +'' )  FROM tasks WHERE task_execution_date = @export_date); 
SELECT @order_ids; -- "1,2,3"

-- method 3
SET @order_ids =  (SELECT GROUP_CONCAT( DISTINCT + '\'' + CAST(task_order AS CHAR (100)) + '\'') FROM tasks WHERE task_execution_date = @export_date); 
SELECT @order_ids; -- "1,2,3"

-- Orders by tasks 
 SELECT * from orders WHERE ordr_id IN (@order_ids);     -- returns only one result
 -- SELECT * from orders WHERE ordr_id IN @order_ids;    -- error
 SELECT * from orders WHERE ordr_id IN ('1', '2', '3');  -- works
 SELECT * from orders WHERE ordr_id IN (SELECT DISTINCT task_order FROM tasks WHERE task_execution_date = @export_date); -- works


-- Also needed: 
-- goods by orders
-- good_adrs by goods

Answer 1

如果您真的，真的，我的意思是真正知道这些变量不可能是邪恶的，那么您可以构建和执行原始查询：

SET @export_date = '2022-06-20';
SET @order_ids = (SELECT GROUP_CONCAT(DISTINCT task_order SEPARATOR ',' )  FROM tasks WHERE task_execution_date = @export_date); 
SET @query = CONCAT('SELECT * from orders WHERE ordr_id IN (', @order_ids, ');');
PREPARE stmt FROM @query;
EXECUTE stmt;