那位大哥知道 求解！

求大侠指点啊，不然我今晚就没得睡了！

看你这么可怜的小盆友，帮你一下吧。
select a,count(b)
from dna
group by a

select
count(case when a = 1 then b end) as 'a=1',
count(case when a = 2 then b end) as 'a=2',
count(case when a = 3 then b end) as 'a=3',
count(case when a = 4 then b end) as 'a=4'
from dna

不能在ACCESS中用，ACCESS的SQL不标准，用了好多VB函数。改一下就能用了。
select
count(IIf( a = 1，b，null ) as 'a=1',
count(IIf( a = 2, b, null) as 'a=2',
count(IIf( a = 3, b, null) as 'a=3',
count(IIf( a = 4, b, null) as 'a=4'
from dna

SELECT
count( IIf( a = 1,b,null )) AS ['a=1'],
count(IIf( a = 2, b, null)) AS ['a=2'],
count(IIf( a = 3, b, null)) AS ['a=3'],
count(IIf( a = 4, b, null)) AS ['a=4']
FROM dna;

SELECT
count(IIf( a = 1, b, null)) AS [a=1],
count(IIf( a = 2, b, null)) AS [a=2],
count(IIf( a = 3, b, null)) AS [a=3],
count(IIf( a = 4, b, null)) AS [a=4]
FROM dna;
你要是单机版处理数据库问题要么来个大而全的SQL server 2005
要么来个SQLite
ACCESS的SQL最烦人了，很多不标准的地方。