Question

这是我的查询，我需要帮助

SELECT MIN(Time) 
FROM `TABLE 1` 
WHERE LevelGuidance="High Guidance" 
AND Task=1 IN (SELECT * FROM `TABLE 1` WHERE Task_ Difficulty="Low")

Answer 1

您不需要子查询甚至IN操作符只需要另一个条件

SELECT MIN(Time) 
FROM `TABLE 1` 
WHERE LevelGuidance='High Guidance' 
AND Task_Difficulty='Low'
AND Task=1

Answer 2

您的子查询写错了。要修复它，您需要在IN（）运算符之前添加特定列。此外，您还需要指定IN运算符正在查看的列

实施例

SELECT MIN(Time) FROM TABLE 1 WHERE LevelGuidance="High Guidance" AND Task=1 and SOMEcolumn IN (SELECT SOMEcolumn FROM TABLE 1 WHERE Task_ Difficulty="Low")

有关IN运算符的更多信息：http://www.w3schools.com/sql/sql_in.asp

操作数应该包含phpMyAdmin中的1列

2 个答案: