sql subqueries, grouping and a bit of math

this counts all items in B and groups on A:

SELECT A, Count(*) AS [Count All]
FROM MyTable 
GROUP BY A;

this counts all 1s in B and groups on A:

SELECT A, Count(*) AS [Count Ones]
FROM My开发者_C百科Table
WHERE
     MyTable.[B]='1' 
GROUP BY A;

How do I put both columns (all and 1s) and additionally, how could I show percentage in another row

table columns:

[A] [COUNT ALL] [COUNT ONES] [ONES/ALL]

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Since its MS-ACCESS you can use iif instead of case

SELECT 
     Table1.A, 
     Sum(IIf([B]=1,1,0)) AS Count1, 
     Count(Table1.A) AS total, 
     (Sum(IIf([B]=1,1,0))/ Count(Table1.A)) * 100 AS percentofones
FROM 
     Table1
GROUP BY 
     Table1.A;