My Table: table1
我的表：table1
ID Name Family 1 A AA 2 B BB 3 A AB 4 D DD 5 E EE 6 A AC
SQL command on Access:
Access上的SQL命令：
select count(*) from table1
Output: ------------> True
6 row(s)
输出：------------>真6行
I tried to count unique names:
我试图计算独特的名字：
Expected output: 4 row(s)
预期产量：4排
select count(distinct Name) from table1
Output on Access: ------------> Error
Access上的输出：------------>错误
What changes do I need to make to my query?
我需要对查询进行哪些更改？
2 个解决方案
#1
33
Try this
尝试这个
SELECT Count(*) AS N
FROM
(SELECT DISTINCT Name FROM table1) AS T;
Read this for more info.
阅读本文以获取更多信息。
#2
7
Access-Engine does not support
Access-Engine不支持
SELECT count(DISTINCT....) FROM ...
You have to do it like this:
你必须这样做：
SELECT count(*)
FROM
(SELECT DISTINCT Name FROM table1)
Its a little workaround... you're counting a DISTINCT selection.
它有点解决方法......你在计算DISTINCT的选择。
#1
33
Try this
尝试这个
SELECT Count(*) AS N
FROM
(SELECT DISTINCT Name FROM table1) AS T;
Read this for more info.
阅读本文以获取更多信息。
#2
7
Access-Engine does not support
Access-Engine不支持
SELECT count(DISTINCT....) FROM ...
You have to do it like this:
你必须这样做：
SELECT count(*)
FROM
(SELECT DISTINCT Name FROM table1)
Its a little workaround... you're counting a DISTINCT selection.
它有点解决方法......你在计算DISTINCT的选择。