就算没有这个值,也可以用默认值表示,但是我发现IFNULL 没有效果,还是只会查有值的数据。因为这个时间点的其他设备名称是有值的,所以我得保证每个值的list的长度是相同的,我是这么写的:
SELECT
IFNULL(p_value ,0) AS pValue,
IFNULL(temperature ,0) AS temperature
FROM
t_p_value_table
WHERE
p_value in (
SELECT
MAX(p_value )
FROM
t_p_value_table
WHERE
sys_date in (select sys_date from t_p_value_table where sys_date >= '2022-03-02'
and sys_date < '2022-04-06' group sys_date )
and name in (select name from name _relation _table GROUP BY name ) GROUP BY name )
求指导