Sql 使用2个WHERE子句将两个select语句合并为一个语句
我正在使用这两个select语句,并希望将它们合并到一个语句中。有人有什么建议吗。但是,问题是我使用的是access,access中没有case子句Sql 使用2个WHERE子句将两个select语句合并为一个语句,sql,database,ms-access,Sql,Database,Ms Access,我正在使用这两个select语句,并希望将它们合并到一个语句中。有人有什么建议吗。但是,问题是我使用的是access,access中没有case子句 SELECT Table_1.Table_Identification_Number, AVG (Table_2.Coulmn-2) AS avg_attribute FROM Table_1 JOIN Table_2 ON Table_1.Table_Identification_Number = Tabl
SELECT
Table_1.Table_Identification_Number,
AVG (Table_2.Coulmn-2) AS avg_attribute
FROM
Table_1 JOIN
Table_2 ON Table_1.Table_Identification_Number = Table_2.Table_Identification_Number
WHERE
Table_2.Column-3='1'
GROUP BY
Table_1.Table_Identification_Number
SELECT
Table_1.Table_Identification_Number,
AVG (Table_2.Coulmn-2) AS avg_attribute
FROM
Table_1 JOIN
Table_2 ON Table_1.Table_Identification_Number = Table_2.Table_Identification_Number
WHERE
Table_2.Column-3='2'
GROUP BY
Table_1.Table_Identification_Number
您似乎需要条件聚合。如果是,您可以在MS Access中将其表示为:
SELECT t1.Table_Identification_Number,
AVG(IIF(t2.Column_3 = 1, t2.Column_2, NULL)) as avg_1,
AVG(IIF(t2.Column_3 = 2, t2.Column_2, NULL)) as avg_2
FROM Table_1 as t1 JOIN
Table_2 as t2
ON t1.Table_Identification_Number = t2.Table_Identification_Number
WHERE t2.Column_3 IN (1, 2)
GROUP BY t1.Table_Identification_Number;
请提供样本数据和预期结果。另外,修复数据库标记以确保数据库的准确性。