如何添加一个字段来计算查询检索到的记录数？为什么我会收到此错误消息？
How can I add a field that count the number of the records retrieved by my query? Why am I obtaining this error message?
我不是很喜欢 SQL，我对尝试更改查询有以下疑问（我正在使用 MySql 作为数据库）。
所以我有这个查询：
SELECT
MD.id AS market_id,
MD.market_name AS market_name,
CN.id AS commodity_details_id,
CD.commodity_name_en AS commodity_name_en,
CN.commodity_name AS commodity_name,
CD.image_link AS image_link,
CN.description AS description,
MD_CD.id AS price_serie_id,
MCPS.avg_price AS today_avg_price,
YMCPS.avg_price AS yesterday_avg_price,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.currency
ELSE
YMCPS.currency
END AS currency,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.measure_unit
ELSE
YMCPS.measure_unit
END AS measure_unit
FROM MarketDetails_CommodityDetails AS MD_CD
INNER JOIN MarketDetails AS MD
ON MD_CD.market_details_id = MD.id
INNER JOIN CommodityDetails as CD
ON MD_CD.commodity_details_id = CD.id
INNER JOIN CommodityName AS CN
ON CD.id=CN.commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = CURDATE()
) AS MCPS
ON MD_CD.id = MCPS.market_commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = ADDDATE(CURDATE(), -1)
) AS YMCPS
ON MD_CD.id = YMCPS.market_commodity_details_id
WHERE
MD_CD.commodity_details_id = 4
AND
MD.localization_id = 2
返回 2 条这样的记录，代表销售特定商品的市场，如下所示：
market_id market_name commodity_details_id commodity_name_en commodity_name image_link description price_serie_id today_avg_price yesterday_avg_price currency measure_unit
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
4 Tambacounda Market N1 4 Red onion Red onion https://firebasestorage.googleapis.com/v0/b/blablabla.appspot.com/o/img%2Ficons%2Fagrimarket%2Fcommodity%2Fonion-red.png?alt=media&token=4ec9de4e-6e5a-4198-9bcd-21b692760618 Red onion 24 20,15 18,94 XOF kilogram
5 Tambacounda Market N2 4 Red onion Red onion https://firebasestorage.googleapis.com/v0/b/blablabla.appspot.com/o/img%2Ficons%2Fagrimarket%2Fcommodity%2Fonion-red.png?alt=media&token=4ec9de4e-6e5a-4198-9bcd-21b692760618 Red onion 28 13,7 16,2 XOF kilogram
好的，我想添加一个新字段来表示可以使用该商品的市场数量（基本上是检索到的记录数量），所以我尝试这样做：
SELECT
MD.id AS market_id,
MD.market_name AS market_name,
count(MD.id) AS market_total_number,
CN.id AS commodity_details_id,
CD.commodity_name_en AS commodity_name_en,
CN.commodity_name AS commodity_name,
CD.image_link AS image_link,
CN.description AS description,
MD_CD.id AS price_serie_id,
MCPS.avg_price AS today_avg_price,
YMCPS.avg_price AS yesterday_avg_price,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.currency
ELSE
YMCPS.currency
END AS currency,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.measure_unit
ELSE
YMCPS.measure_unit
END AS measure_unit
FROM MarketDetails_CommodityDetails AS MD_CD
INNER JOIN MarketDetails AS MD
ON MD_CD.market_details_id = MD.id
INNER JOIN CommodityDetails as CD
ON MD_CD.commodity_details_id = CD.id
INNER JOIN CommodityName AS CN
ON CD.id=CN.commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = CURDATE()
) AS MCPS
ON MD_CD.id = MCPS.market_commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = ADDDATE(CURDATE(), -1)
) AS YMCPS
ON MD_CD.id = YMCPS.market_commodity_details_id
WHERE
MD_CD.commodity_details_id = 4
AND
MD.localization_id = 2
我只是将此 SELECT 添加到检索字段列表中：
count(MD.id) AS market_total_number,
因为我的想法是对检索到的记录进行计数，但是现在执行我的查询时我收到了这个错误消息：
#42000In aggregated query without GROUP BY, expression #1 of SELECT list contains nonaggregated column 'digital_services_DB.MD.id'; this is incompatible with sql_mode=only_full_group_by
为什么？怎么了？我错过了什么？我怎样才能解决这个问题并获得预期的结果？
使用聚合函数时，分组依据是必需的。
试试这个
SELECT count(market_id) AS market_total_number,
market_id,
market_name,
market_total_number,
commodity_details_id,
commodity_name_en,
commodity_name,
image_link,
description,
price_serie_id,
today_avg_price,
yesterday_avg_price,
currency ,
measure_units
FROM (
SELECT
MD.id AS market_id,
MD.market_name AS market_name,
count(MD.id) AS market_total_number,
CN.id AS commodity_details_id,
CD.commodity_name_en AS commodity_name_en,
CN.commodity_name AS commodity_name,
CD.image_link AS image_link,
CN.description AS description,
MD_CD.id AS price_serie_id,
MCPS.avg_price AS today_avg_price,
YMCPS.avg_price AS yesterday_avg_price,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.currency
ELSE
YMCPS.currency
END AS currency,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.measure_unit
ELSE
YMCPS.measure_unit
END AS measure_unit
FROM MarketDetails_CommodityDetails AS MD_CD
INNER JOIN MarketDetails AS MD
ON MD_CD.market_details_id = MD.id
INNER JOIN CommodityDetails as CD
ON MD_CD.commodity_details_id = CD.id
INNER JOIN CommodityName AS CN
ON CD.id=CN.commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = CURDATE()
) AS MCPS
ON MD_CD.id = MCPS.market_commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = ADDDATE(CURDATE(), -1)
) AS YMCPS
ON MD_CD.id = YMCPS.market_commodity_details_id
WHERE
MD_CD.commodity_details_id = 4
AND
MD.localization_id = 2
) base
group by market_id,
market_name,
market_total_number,
commodity_details_id,
commodity_name_en,
commodity_name,
image_link,
description,
price_serie_id,
today_avg_price,
yesterday_avg_price,
currency ,
measure_units
当您想创建一个 select 具有聚合函数（如计数）并检索任何字段时，您必须使用分组依据。
您可以在以下位置阅读更多相关信息：
https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html
因此，如果您在查询末尾添加它，它将起作用。
GROUP BY
MD.id
,MD.market_name
,CN.id
,CD.commodity_name_en
,CN.commodity_name
,CD.image_link
,CN.description
,MD_CD.id
,MCPS.avg_price
,YMCPS.avg_price
我不是很喜欢 SQL，我对尝试更改查询有以下疑问（我正在使用 MySql 作为数据库）。
所以我有这个查询：
SELECT
MD.id AS market_id,
MD.market_name AS market_name,
CN.id AS commodity_details_id,
CD.commodity_name_en AS commodity_name_en,
CN.commodity_name AS commodity_name,
CD.image_link AS image_link,
CN.description AS description,
MD_CD.id AS price_serie_id,
MCPS.avg_price AS today_avg_price,
YMCPS.avg_price AS yesterday_avg_price,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.currency
ELSE
YMCPS.currency
END AS currency,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.measure_unit
ELSE
YMCPS.measure_unit
END AS measure_unit
FROM MarketDetails_CommodityDetails AS MD_CD
INNER JOIN MarketDetails AS MD
ON MD_CD.market_details_id = MD.id
INNER JOIN CommodityDetails as CD
ON MD_CD.commodity_details_id = CD.id
INNER JOIN CommodityName AS CN
ON CD.id=CN.commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = CURDATE()
) AS MCPS
ON MD_CD.id = MCPS.market_commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = ADDDATE(CURDATE(), -1)
) AS YMCPS
ON MD_CD.id = YMCPS.market_commodity_details_id
WHERE
MD_CD.commodity_details_id = 4
AND
MD.localization_id = 2
返回 2 条这样的记录，代表销售特定商品的市场，如下所示：
market_id market_name commodity_details_id commodity_name_en commodity_name image_link description price_serie_id today_avg_price yesterday_avg_price currency measure_unit
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
4 Tambacounda Market N1 4 Red onion Red onion https://firebasestorage.googleapis.com/v0/b/blablabla.appspot.com/o/img%2Ficons%2Fagrimarket%2Fcommodity%2Fonion-red.png?alt=media&token=4ec9de4e-6e5a-4198-9bcd-21b692760618 Red onion 24 20,15 18,94 XOF kilogram
5 Tambacounda Market N2 4 Red onion Red onion https://firebasestorage.googleapis.com/v0/b/blablabla.appspot.com/o/img%2Ficons%2Fagrimarket%2Fcommodity%2Fonion-red.png?alt=media&token=4ec9de4e-6e5a-4198-9bcd-21b692760618 Red onion 28 13,7 16,2 XOF kilogram
好的，我想添加一个新字段来表示可以使用该商品的市场数量（基本上是检索到的记录数量），所以我尝试这样做：
SELECT
MD.id AS market_id,
MD.market_name AS market_name,
count(MD.id) AS market_total_number,
CN.id AS commodity_details_id,
CD.commodity_name_en AS commodity_name_en,
CN.commodity_name AS commodity_name,
CD.image_link AS image_link,
CN.description AS description,
MD_CD.id AS price_serie_id,
MCPS.avg_price AS today_avg_price,
YMCPS.avg_price AS yesterday_avg_price,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.currency
ELSE
YMCPS.currency
END AS currency,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.measure_unit
ELSE
YMCPS.measure_unit
END AS measure_unit
FROM MarketDetails_CommodityDetails AS MD_CD
INNER JOIN MarketDetails AS MD
ON MD_CD.market_details_id = MD.id
INNER JOIN CommodityDetails as CD
ON MD_CD.commodity_details_id = CD.id
INNER JOIN CommodityName AS CN
ON CD.id=CN.commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = CURDATE()
) AS MCPS
ON MD_CD.id = MCPS.market_commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = ADDDATE(CURDATE(), -1)
) AS YMCPS
ON MD_CD.id = YMCPS.market_commodity_details_id
WHERE
MD_CD.commodity_details_id = 4
AND
MD.localization_id = 2
我只是将此 SELECT 添加到检索字段列表中：
count(MD.id) AS market_total_number,
因为我的想法是对检索到的记录进行计数，但是现在执行我的查询时我收到了这个错误消息：
#42000In aggregated query without GROUP BY, expression #1 of SELECT list contains nonaggregated column 'digital_services_DB.MD.id'; this is incompatible with sql_mode=only_full_group_by
为什么？怎么了？我错过了什么？我怎样才能解决这个问题并获得预期的结果？
使用聚合函数时，分组依据是必需的。 试试这个
SELECT count(market_id) AS market_total_number,
market_id,
market_name,
market_total_number,
commodity_details_id,
commodity_name_en,
commodity_name,
image_link,
description,
price_serie_id,
today_avg_price,
yesterday_avg_price,
currency ,
measure_units
FROM (
SELECT
MD.id AS market_id,
MD.market_name AS market_name,
count(MD.id) AS market_total_number,
CN.id AS commodity_details_id,
CD.commodity_name_en AS commodity_name_en,
CN.commodity_name AS commodity_name,
CD.image_link AS image_link,
CN.description AS description,
MD_CD.id AS price_serie_id,
MCPS.avg_price AS today_avg_price,
YMCPS.avg_price AS yesterday_avg_price,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.currency
ELSE
YMCPS.currency
END AS currency,
CASE WHEN MCPS.market_commodity_details_id IS NOT NULL
THEN
MCPS.measure_unit
ELSE
YMCPS.measure_unit
END AS measure_unit
FROM MarketDetails_CommodityDetails AS MD_CD
INNER JOIN MarketDetails AS MD
ON MD_CD.market_details_id = MD.id
INNER JOIN CommodityDetails as CD
ON MD_CD.commodity_details_id = CD.id
INNER JOIN CommodityName AS CN
ON CD.id=CN.commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = CURDATE()
) AS MCPS
ON MD_CD.id = MCPS.market_commodity_details_id
LEFT JOIN
(
SELECT
Market_Commodity_Price_Series.id AS price_series_id,
market_commodity_details_id
, avg_price
, CU.ISO_4217_cod AS currency
, MU.unit_name AS measure_unit
FROM Market_Commodity_Price_Series
INNER JOIN MeasureUnit AS MU
ON Market_Commodity_Price_Series.measure_unit_id = MU.id
INNER JOIN Currency AS CU
ON Market_Commodity_Price_Series.currency_id = CU.id
WHERE price_date = ADDDATE(CURDATE(), -1)
) AS YMCPS
ON MD_CD.id = YMCPS.market_commodity_details_id
WHERE
MD_CD.commodity_details_id = 4
AND
MD.localization_id = 2
) base
group by market_id,
market_name,
market_total_number,
commodity_details_id,
commodity_name_en,
commodity_name,
image_link,
description,
price_serie_id,
today_avg_price,
yesterday_avg_price,
currency ,
measure_units
当您想创建一个 select 具有聚合函数（如计数）并检索任何字段时，您必须使用分组依据。
您可以在以下位置阅读更多相关信息： https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html
因此，如果您在查询末尾添加它，它将起作用。
GROUP BY
MD.id
,MD.market_name
,CN.id
,CD.commodity_name_en
,CN.commodity_name
,CD.image_link
,CN.description
,MD_CD.id
,MCPS.avg_price
,YMCPS.avg_price