Question

我使用了以下stackoverflow帖子来尝试获取最新日期的记录： Select info from table where row has max date

我写了以下查询：

SELECT AR_SQ.SYMBOL, AR_SQ.NAME, AR_SQ.LAST, FF_PS.SECTOR, FF_PS.SECTOR_TAGS, HP.LAST_10_DAYS, HP.YTD_PERF 
FROM AR_STOCK_QUOTE AR_SQ 
LEFT JOIN (
SELECT HP.SYMBOL, max(TRADE_DATE) as MaxDate 
FROM FF_HISTORICAL_STOCK_PRICE HP
GROUP BY HP.SYMBOL
) 
HP on HP.SYMBOL = AR_SQ.SYMBOL 
JOIN FF_PRIMARY_STOCK_TABLE FF_PS on FF_PS.SYMBOL = AR_SQ.SYMBOL

当我这样做时，我收到一条错误消息，说明如下：

错误代码：1054。“字段列表”中的未知列“HP.LAST_10_DAYS”

为什么会出现这种情况，因为定义了HP并且它是该表中的一个字段？

Answer 1

因为你在select语句上进行连接而不是表＆＃34; FF_HISTORICAL_STOCK_PRICE＆＃34;您无法在全局选择中使用HP，因为HP未在此处定义

SELECT AR_SQ.SYMBOL, AR_SQ.NAME, AR_SQ.LAST, FF_PS.SECTOR, FF_PS.SECTOR_TAGS, HP.LAST_10_DAYS, HP.YTD_PERF  #3- you cannot use HP here
FROM AR_STOCK_QUOTE AR_SQ 
LEFT JOIN (
# 1- you are not doing ajoin on the table FF_HISTORICAL_STOCK_PRICE HP
# 2- you can use HP on this select 
SELECT HP.SYMBOL, max(TRADE_DATE) as MaxDate 
FROM FF_HISTORICAL_STOCK_PRICE HP
GROUP BY HP.SYMBOL
) 
HP on HP.SYMBOL = AR_SQ.SYMBOL 
JOIN FF_PRIMARY_STOCK_TABLE FF_PS on FF_PS.SYMBOL = AR_SQ.SYMBOLenter code here

将字段添加到连接部分中的select语句，现在它们将存在于结果HP上，并尝试为选择使用不同的别名

SELECT AR_SQ.SYMBOL, AR_SQ.NAME, AR_SQ.LAST, FF_PS.SECTOR, FF_PS.SECTOR_TAGS, RS.LAST_10_DAYS, RS.YTD_PERF 
FROM AR_STOCK_QUOTE AR_SQ 
LEFT JOIN (
# add the last_10_days to the fields of you select statement now you can select them
SELECT HP.SYMBOL, max(TRADE_DATE) as MaxDate ,HP.LAST_10_DAYS, HP.YTD_PERF 
FROM FF_HISTORICAL_STOCK_PRICE HP
GROUP BY HP.SYMBOL
) RS on RS.SYMBOL = AR_SQ.SYMBOL  #HP is a result of select statement 
JOIN FF_PRIMARY_STOCK_TABLE FF_PS on FF_PS.SYMBOL = AR_SQ.SYMBOL

连接表和使用子查询时的未知列

1 个答案: