mysql - Java 中的 SQL；处理 SELECT 和 GROUP BY 时出错

Question

首先，我是 SQL 方面的 super 新手，所以我不具备提出简单问题的知识，但我会尽力而为。这是我试图提出的查询:

query = conn1.prepareStatement(
"select Industry, Ticker, TransDate, min(TransDate), max(TransDate), " +
"     count(distinct TransDate) as TradingDays, " +
"     count(distinct Ticker) as TickerCnt, " +
"     openPrice, closePrice " +
"  from  Company left outer join PriceVolume using(Ticker) " +
"  group by Industry " +
"  having TradingDays >= 150 " +
"  order by Industry, Ticker, TransDate");
ResultSet rs = query.executeQuery();

错误如下: SQLException: Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'reedy330.Company.Ticker' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

如果我在 GROUP BY 子句中包含 Ticker 和 TransDate，则不再发生异常，但 ResultSet是空的。我想做的是 ResultSet一切都在 SELECT子句作为元素。我根据作业描述中的类似示例查询构建了此查询，这就是我不太理解它的原因。

这是数据库的布局，表名用冒号加粗，键以粗体显示:

PriceVolume:
Ticker
TransDate
OpenPrice
HighPrice
LowPrice
ClosePrice
Volume
AdjustedGross

Company:
Ticker
Name
Industry
Location

有什么想法吗？

Answer 1

“sql_mode=only_full_group_by”对您来说是必要的吗？

如果没有，请更改sql_mode:

SET sql_mode = '';

或者

SET sql_mode = 'STRICT_ALL_TABLES';