我想知道SQL中是否有一种简单的方法可以将整数转换为二进制表示,然后将其存储为varchar。
例如,5将被转换为“101”并存储为varchar。
我想知道SQL中是否有一种简单的方法可以将整数转换为二进制表示,然后将其存储为varchar。
例如,5将被转换为“101”并存储为varchar。
以下内容可以编码为一个函数。您需要去掉前导零以满足问题的要求。
declare @intvalue int
set @intvalue=5
declare @vsresult varchar(64)
declare @inti int
select @inti = 64, @vsresult =
while @inti>0
begin
select @vsresult=convert(char(1), @intvalue % 2)+@vsresult
select @intvalue = convert(int, (@intvalue / 2)), @inti=@inti-1
end
select @vsresult
事实上,使用普通的旧SQL非常简单。只需使用位AND。我有点惊讶,网上没有发布一个简单的解决方案(不调用UDF)。在我的情况下,我真的想检查比特是开还是关(数据来自dotnet eNums)。
因此,这里有一个例子,它将分别给出位值和二进制字符串(大并集只是一种生成跨数据库的数字的方法:
select t.Number
, cast(t.Number & 64 as bit) as bit7
, cast(t.Number & 32 as bit) as bit6
, cast(t.Number & 16 as bit) as bit5
, cast(t.Number & 8 as bit) as bit4
, cast(t.Number & 4 as bit) as bit3
, cast(t.Number & 2 as bit) as bit2
,cast(t.Number & 1 as bit) as bit1
, cast(cast(t.Number & 64 as bit) as CHAR(1))
+cast( cast(t.Number & 32 as bit) as CHAR(1))
+cast( cast(t.Number & 16 as bit) as CHAR(1))
+cast( cast(t.Number & 8 as bit) as CHAR(1))
+cast( cast(t.Number & 4 as bit) as CHAR(1))
+cast( cast(t.Number & 2 as bit) as CHAR(1))
+cast(cast(t.Number & 1 as bit) as CHAR(1)) as binary_string
--to explicitly answer the question, on MSSQL without using REGEXP (which would make it simple)
,SUBSTRING(cast(cast(t.Number & 64 as bit) as CHAR(1))
+cast( cast(t.Number & 32 as bit) as CHAR(1))
+cast( cast(t.Number & 16 as bit) as CHAR(1))
+cast( cast(t.Number & 8 as bit) as CHAR(1))
+cast( cast(t.Number & 4 as bit) as CHAR(1))
+cast( cast(t.Number & 2 as bit) as CHAR(1))
+cast(cast(t.Number & 1 as bit) as CHAR(1))
,
PATINDEX( %1% , cast(cast(t.Number & 64 as bit) as CHAR(1))
+cast( cast(t.Number & 32 as bit) as CHAR(1))
+cast( cast(t.Number & 16 as bit) as CHAR(1))
+cast( cast(t.Number & 8 as bit) as CHAR(1))
+cast( cast(t.Number & 4 as bit) as CHAR(1))
+cast( cast(t.Number & 2 as bit) as CHAR(1))
+cast(cast(t.Number & 1 as bit) as CHAR(1) )
)
,99)
from (select 1 as Number union all select 2 union all select 3 union all select 4 union all select 5 union all select 6
union all select 7 union all select 8 union all select 9 union all select 10) as t
产生以下结果:
num bit7 bit6 bit5 bit4 bit3 bit2 bit1 binary_string binary_string_trimmed
1 0 0 0 0 0 0 1 0000001 1
2 0 0 0 0 0 1 0 0000010 10
3 0 0 0 0 0 1 1 0000011 11
4 0 0 0 1 0 0 0 0000100 100
5 0 0 0 0 1 0 1 0000101 101
6 0 0 0 0 1 1 0 0000110 110
7 0 0 0 0 1 1 1 0000111 111
8 0 0 0 1 0 0 0 0001000 1000
9 0 0 0 1 0 0 1 0001001 1001
10 0 0 0 1 0 1 0 0001010 1010
这是一个通用的基本转换器
http://dpatrickcaldwell.blogspot.com/2009/05/converting-decimal-to-hexadecimal-with.html
你可以
select reverse(dbo.ConvertToBase(5, 2)) -- 101
Create function f_DecimalToBinaryString
(
@Dec int,
@MaxLength int = null
)
Returns varchar(max)
as Begin
Declare @BinStr varchar(max) = ;
-- Perform the translation from Dec to Bin
While @Dec > 0 Begin
Set @BinStr = Convert(char(1), @Dec % 2) + @BinStr;
Set @Dec = Convert(int, @Dec /2);
End;
-- Either pad or trim the output to match the number of digits specified.
If (@MaxLength is not null) Begin
If @MaxLength <= Len(@BinStr) Begin -- Trim down
Set @BinStr = SubString(@BinStr, Len(@BinStr) - (@MaxLength - 1), @MaxLength);
End Else Begin -- Pad up
Set @BinStr = Replicate( 0 , @MaxLength - Len(@BinStr)) + @BinStr;
End;
End;
Return @BinStr;
End;
declare @i int /* input */
set @i = 42
declare @result varchar(32) /* SQL Server int is 32 bits wide */
set @result =
while 1 = 1 begin
select @result = convert(char(1), @i % 2) + @result,
@i = convert(int, @i / 2)
if @i = 0 break
end
select @result
I used the following ITVF function to convert from decimal to Binary as it is a inline function you don t need to "worry" about multiple reads performed by the optimizer.
CREATE FUNCTION dbo.udf_DecimalToBinary
(
@Decimal VARCHAR(32)
)
RETURNS TABLE AS RETURN
WITH Tally (n) AS
(
--32 Rows
SELECT TOP 30 ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) -1
FROM (VALUES (0),(0),(0),(0)) a(n)
CROSS JOIN (VALUES(0),(0),(0),(0),(0),(0),(0),(0)) b(n)
)
, Anchor (n, divisor , Result) as
(
SELECT t.N ,
CONVERT(BIGINT, @Decimal) / POWER(2,T.N) ,
CONVERT(BIGINT, @Decimal) / POWER(2,T.N) % 2
FROM Tally t
WHERE CONVERT(bigint,@Decimal) >= POWER(2,t.n)
)
SELECT TwoBaseBinary = +
(SELECT Result
FROM Anchor
ORDER BY N DESC
FOR XML PATH ( ) , TYPE).value( . , varchar(200) )
/*How to use*/
SELECT TwoBaseBinary
FROM dbo.udf_DecimalToBinary ( 1234 )
/*result -> 10011010010*/
declare @intVal Int
set @intVal = power(2,12)+ power(2,5) + power(2,1);
With ComputeBin (IntVal, BinVal,FinalBin)
As
(
Select @IntVal IntVal, @intVal %2 BinVal , convert(nvarchar(max),(@intVal %2 )) FinalBin
Union all
Select IntVal /2, (IntVal /2) %2, convert(nvarchar(max),(IntVal /2) %2) + FinalBin FinalBin
From ComputeBin
Where IntVal /2 > 0
)
select FinalBin from ComputeBin where intval = ( select min(intval) from ComputeBin);
with t as (select * from (values (0),(1)) as t(c)),
t0 as (table t),
t1 as (table t),
t2 as (table t),
t3 as (table t),
t4 as (table t),
t5 as (table t),
t6 as (table t),
t7 as (table t),
t8 as (table t),
t9 as (table t),
ta as (table t),
tb as (table t),
tc as (table t),
td as (table t),
te as (table t),
tf as (table t)
select || t0.c || t1.c || t2.c || t3.c || t4.c || t5.c || t6.c || t7.c || t8.c || t9.c || ta.c || tb.c || tc.c || td.c || te.c || tf.c as n
from t0,t1,t2,t3,t4,t5,t6,t7,t8,t9,ta,tb,tc,td,te,tf
order by n
limit 1 offset 5
标准SQL(在PostgreSQL中测试)。
在SQL Server上,您可以尝试下面的示例:
DECLARE @Int int = 321
SELECT @Int
,CONCAT
(CAST(@Int & power(2,15) AS bit)
,CAST(@Int & power(2,14) AS bit)
,CAST(@Int & power(2,13) AS bit)
,CAST(@Int & power(2,12) AS bit)
,CAST(@Int & power(2,11) AS bit)
,CAST(@Int & power(2,10) AS bit)
,CAST(@Int & power(2,9) AS bit)
,CAST(@Int & power(2,8) AS bit)
,CAST(@Int & power(2,7) AS bit)
,CAST(@Int & power(2,6) AS bit)
,CAST(@Int & power(2,5) AS bit)
,CAST(@Int & power(2,4) AS bit)
,CAST(@Int & power(2,3) AS bit)
,CAST(@Int & power(2,2) AS bit)
,CAST(@Int & power(2,1) AS bit)
,CAST(@Int & power(2,0) AS bit) ) AS BitString
,CAST(@Int & power(2,15) AS bit) AS BIT15
,CAST(@Int & power(2,14) AS bit) AS BIT14
,CAST(@Int & power(2,13) AS bit) AS BIT13
,CAST(@Int & power(2,12) AS bit) AS BIT12
,CAST(@Int & power(2,11) AS bit) AS BIT11
,CAST(@Int & power(2,10) AS bit) AS BIT10
,CAST(@Int & power(2,9) AS bit) AS BIT9
,CAST(@Int & power(2,8) AS bit) AS BIT8
,CAST(@Int & power(2,7) AS bit) AS BIT7
,CAST(@Int & power(2,6) AS bit) AS BIT6
,CAST(@Int & power(2,5) AS bit) AS BIT5
,CAST(@Int & power(2,4) AS bit) AS BIT4
,CAST(@Int & power(2,3) AS bit) AS BIT3
,CAST(@Int & power(2,2) AS bit) AS BIT2
,CAST(@Int & power(2,1) AS bit) AS BIT1
,CAST(@Int & power(2,0) AS bit) AS BIT0
我知道我在这里玩游戏有点晚了,但我最近想出了一个巧妙的解决方案,它利用了一个计数表(类似于上面的@hkravitz解决方案。)关键的区别是,我利用了我所说的虚拟索引,以降序对结果进行排序,而在执行计划中没有排序运算符。我使用dbo.rangeAB
实现了这一点,它包含在本文的末尾。
请注意,这将按升序返回数字0到30(作为RowNumber的“RN”):
SELECT r.RN
FROM dbo.rangeAB(0,30,1,0) AS r
ORDER BY r.RN;
它这样做没有排序。RN可以定义为ROW_NUMBER()OVER(ORDER BY(SELECT NULL))。RN排序不需要排序,这也是虚拟索引的作用。
当我尝试降序排序时,我会在执行计划中进行排序。
输入有限对手。RangeAB包括一个名为Op-Op RN s有限Op位置编号的列。我所说的“有限对立”是指,0是30的对立,1是29的对立,等等。与传统的对立数字不同(-1是1的对立)。有限的对立面按降序返回。
SELECT r.RN, r.OP
FROM dbo.rangeAB(0,30,1,0) AS r
ORDER BY r.RN;
返回:
RN OP
----- -------
0 30
1 29
2 28
3 27
....
27 3
28 2
29 1
30 0
我可以使用Op。我可以利用RN的有限相反来按降序获取数字,同时仍然利用虚拟索引来避免排序。这两个查询返回相同的东西,但在比较执行计划时,根据SSMS,删除排序将查询成本降低了50倍。
功能
CREATE FUNCTION dbo.NumberToBinary(@input INT)
RETURNS TABLE WITH SCHEMABINDING AS RETURN
/* Created By Alan Burstein 20191112, Requires RangeAB (code below) */
SELECT BIN = (
SELECT @input/f.Np2%2
FROM dbo.rangeAB(0,30,1,0) AS r
CROSS APPLY (VALUES(POWER(2,r.Op))) AS f(NP2)
WHERE (@input = 0 AND f.Np2 = 1) OR @input >= f.Np2
ORDER BY ROW_NUMBER() OVER (ORDER BY (SELECT NULL))
FOR XML PATH( ));
范围AB
CREATE FUNCTION dbo.rangeAB
(
@low bigint,
@high bigint,
@gap bigint,
@row1 bit
)
/****************************************************************************************
[Purpose]:
Creates up to 531,441,000,000 sequentia1 integers numbers beginning with @low and ending
with @high. Used to replace iterative methods such as loops, cursors and recursive CTEs
to solve SQL problems. Based on Itzik Ben-Gan s getnums function with some tweeks and
enhancements and added functionality. The logic for getting rn to begin at 0 or 1 is
based comes from Jeff Moden s fnTally function.
The name range because it s similar to clojure s range function. The name "rangeAB" as
used because "range" is a reserved SQL keyword.
[Author]: Alan Burstein
[Compatibility]:
SQL Server 2008+ and Azure SQL Database
[Syntax]:
SELECT r.RN, r.OP, r.N1, r.N2
FROM dbo.rangeAB(@low,@high,@gap,@row1) AS r;
[Parameters]:
@low = a bigint that represents the lowest value for n1.
@high = a bigint that represents the highest value for n1.
@gap = a bigint that represents how much n1 and n2 will increase each row; @gap also
represents the difference between n1 and n2.
@row1 = a bit that represents the first value of rn. When @row = 0 then rn begins
at 0, when @row = 1 then rn will begin at 1.
[Returns]:
Inline Table Valued Function returns:
rn = bigint; a row number that works just like T-SQL ROW_NUMBER() except that it can
start at 0 or 1 which is dictated by @row1.
op = bigint; returns the "opposite number that relates to rn. When rn begins with 0 and
ends with 10 then 10 is the opposite of 0, 9 the opposite of 1, etc. When rn begins
with 1 and ends with 5 then 1 is the opposite of 5, 2 the opposite of 4, etc...
n1 = bigint; a sequential number starting at the value of @low and incrimentingby the
value of @gap until it is less than or equal to the value of @high.
n2 = bigint; a sequential number starting at the value of @low+@gap and incrimenting
by the value of @gap.
[Dependencies]:
N/A
[Developer Notes]:
1. The lowest and highest possible numbers returned are whatever is allowable by a
bigint. The function, however, returns no more than 531,441,000,000 rows (8100^3).
2. @gap does not affect rn, rn will begin at @row1 and increase by 1 until the last row
unless its used in a query where a filter is applied to rn.
3. @gap must be greater than 0 or the function will not return any rows.
4. Keep in mind that when @row1 is 0 then the highest row-number will be the number of
rows returned minus 1
5. If you only need is a sequential set beginning at 0 or 1 then, for best performance
use the RN column. Use N1 and/or N2 when you need to begin your sequence at any
number other than 0 or 1 or if you need a gap between your sequence of numbers.
6. Although @gap is a bigint it must be a positive integer or the function will
not return any rows.
7. The function will not return any rows when one of the following conditions are true:
* any of the input parameters are NULL
* @high is less than @low
* @gap is not greater than 0
To force the function to return all NULLs instead of not returning anything you can
add the following code to the end of the query:
UNION ALL
SELECT NULL, NULL, NULL, NULL
WHERE NOT (@high&@low&@gap&@row1 IS NOT NULL AND @high >= @low AND @gap > 0)
This code was excluded as it adds a ~5% performance penalty.
8. There is no performance penalty for sorting by rn ASC; there is a large performance
penalty for sorting in descending order WHEN @row1 = 1; WHEN @row1 = 0
If you need a descending sort the use op in place of rn then sort by rn ASC.
Best Practices:
--===== 1. Using RN (rownumber)
-- (1.1) The best way to get the numbers 1,2,3...@high (e.g. 1 to 5):
SELECT RN FROM dbo.rangeAB(1,5,1,1);
-- (1.2) The best way to get the numbers 0,1,2...@high-1 (e.g. 0 to 5):
SELECT RN FROM dbo.rangeAB(0,5,1,0);
--===== 2. Using OP for descending sorts without a performance penalty
-- (2.1) The best way to get the numbers 5,4,3...@high (e.g. 5 to 1):
SELECT op FROM dbo.rangeAB(1,5,1,1) ORDER BY rn ASC;
-- (2.2) The best way to get the numbers 0,1,2...@high-1 (e.g. 5 to 0):
SELECT op FROM dbo.rangeAB(1,6,1,0) ORDER BY rn ASC;
--===== 3. Using N1
-- (3.1) To begin with numbers other than 0 or 1 use N1 (e.g. -3 to 3):
SELECT N1 FROM dbo.rangeAB(-3,3,1,1);
-- (3.2) ROW_NUMBER() is built in. If you want a ROW_NUMBER() include RN:
SELECT RN, N1 FROM dbo.rangeAB(-3,3,1,1);
-- (3.3) If you wanted a ROW_NUMBER() that started at 0 you would do this:
SELECT RN, N1 FROM dbo.rangeAB(-3,3,1,0);
--===== 4. Using N2 and @gap
-- (4.1) To get 0,10,20,30...100, set @low to 0, @high to 100 and @gap to 10:
SELECT N1 FROM dbo.rangeAB(0,100,10,1);
-- (4.2) Note that N2=N1+@gap; this allows you to create a sequence of ranges.
-- For example, to get (0,10),(10,20),(20,30).... (90,100):
SELECT N1, N2 FROM dbo.rangeAB(0,90,10,1);
-- (4.3) Remember that a rownumber is included and it can begin at 0 or 1:
SELECT RN, N1, N2 FROM dbo.rangeAB(0,90,10,1);
[Examples]:
--===== 1. Generating Sample data (using rangeAB to create "dummy rows")
-- The query below will generate 10,000 ids and random numbers between 50,000 and 500,000
SELECT
someId = r.rn,
someNumer = ABS(CHECKSUM(NEWID())%450000)+50001
FROM rangeAB(1,10000,1,1) r;
--===== 2. Create a series of dates; rn is 0 to include the first date in the series
DECLARE @startdate DATE = 20180101 , @enddate DATE = 20180131 ;
SELECT r.rn, calDate = DATEADD(dd, r.rn, @startdate)
FROM dbo.rangeAB(1, DATEDIFF(dd,@startdate,@enddate),1,0) r;
GO
--===== 3. Splitting (tokenizing) a string with fixed sized items
-- given a delimited string of identifiers that are always 7 characters long
DECLARE @string VARCHAR(1000) = A601225,B435223,G008081,R678567 ;
SELECT
itemNumber = r.rn, -- item s ordinal position
itemIndex = r.n1, -- item s position in the string (it s CHARINDEX value)
item = SUBSTRING(@string, r.n1, 7) -- item (token)
FROM dbo.rangeAB(1, LEN(@string), 8,1) r;
GO
--===== 4. Splitting (tokenizing) a string with random delimiters
DECLARE @string VARCHAR(1000) = ABC123,999F,XX,9994443335 ;
SELECT
itemNumber = ROW_NUMBER() OVER (ORDER BY r.rn), -- item s ordinal position
itemIndex = r.n1+1, -- item s position in the string (it s CHARINDEX value)
item = SUBSTRING
(
@string,
r.n1+1,
ISNULL(NULLIF(CHARINDEX( , ,@string,r.n1+1),0)-r.n1-1, 8000)
) -- item (token)
FROM dbo.rangeAB(0,DATALENGTH(@string),1,1) r
WHERE SUBSTRING(@string,r.n1,1) = , OR r.n1 = 0;
-- logic borrowed from: http://www.sqlservercentral.com/articles/Tally+Table/72993/
--===== 5. Grouping by a weekly intervals
-- 5.1. how to create a series of start/end dates between @startDate & @endDate
DECLARE @startDate DATE = 1/1/2015 , @endDate DATE = 2/1/2015 ;
SELECT
WeekNbr = r.RN,
WeekStart = DATEADD(DAY,r.N1,@StartDate),
WeekEnd = DATEADD(DAY,r.N2-1,@StartDate)
FROM dbo.rangeAB(0,datediff(DAY,@StartDate,@EndDate),7,1) r;
GO
-- 5.2. LEFT JOIN to the weekly interval table
BEGIN
DECLARE @startDate datetime = 1/1/2015 , @endDate datetime = 2/1/2015 ;
-- sample data
DECLARE @loans TABLE (loID INT, lockDate DATE);
INSERT @loans SELECT r.rn, DATEADD(dd, ABS(CHECKSUM(NEWID())%32), @startDate)
FROM dbo.rangeAB(1,50,1,1) r;
-- solution
SELECT
WeekNbr = r.RN,
WeekStart = dt.WeekStart,
WeekEnd = dt.WeekEnd,
total = COUNT(l.lockDate)
FROM dbo.rangeAB(0,datediff(DAY,@StartDate,@EndDate),7,1) r
CROSS APPLY (VALUES (
CAST(DATEADD(DAY,r.N1,@StartDate) AS DATE),
CAST(DATEADD(DAY,r.N2-1,@StartDate) AS DATE))) dt(WeekStart,WeekEnd)
LEFT JOIN @loans l ON l.lockDate BETWEEN dt.WeekStart AND dt.WeekEnd
GROUP BY r.RN, dt.WeekStart, dt.WeekEnd ;
END;
--===== 6. Identify the first vowel and last vowel in a along with their positions
DECLARE @string VARCHAR(200) = This string has vowels ;
SELECT TOP(1) position = r.rn, letter = SUBSTRING(@string,r.rn,1)
FROM dbo.rangeAB(1,LEN(@string),1,1) r
WHERE SUBSTRING(@string,r.rn,1) LIKE %[aeiou]%
ORDER BY r.rn;
-- To avoid a sort in the execution plan we ll use op instead of rn
SELECT TOP(1) position = r.op, letter = SUBSTRING(@string,r.op,1)
FROM dbo.rangeAB(1,LEN(@string),1,1) r
WHERE SUBSTRING(@string,r.rn,1) LIKE %[aeiou]%
ORDER BY r.rn;
---------------------------------------------------------------------------------------
[Revision History]:
Rev 00 - 20140518 - Initial Development - Alan Burstein
Rev 01 - 20151029 - Added 65 rows to make L1=465; 465^3=100.5M. Updated comment section
- Alan Burstein
Rev 02 - 20180613 - Complete re-design including opposite number column (op)
Rev 03 - 20180920 - Added additional CROSS JOIN to L2 for 530B rows max - Alan Burstein
****************************************************************************************/
RETURNS TABLE WITH SCHEMABINDING AS RETURN
WITH L1(N) AS
(
SELECT 1
FROM (VALUES
(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),
(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),
(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),
(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),
(0),(0)) T(N) -- 90 values
),
L2(N) AS (SELECT 1 FROM L1 a CROSS JOIN L1 b CROSS JOIN L1 c),
iTally AS (SELECT rn = ROW_NUMBER() OVER (ORDER BY (SELECT 1)) FROM L2 a CROSS JOIN L2 b)
SELECT
r.RN,
r.OP,
r.N1,
r.N2
FROM
(
SELECT
RN = 0,
OP = (@high-@low)/@gap,
N1 = @low,
N2 = @gap+@low
WHERE @row1 = 0
UNION ALL -- ISNULL required in the TOP statement below for error handling purposes
SELECT TOP (ABS((ISNULL(@high,0)-ISNULL(@low,0))/ISNULL(@gap,0)+ISNULL(@row1,1)))
RN = i.rn,
OP = (@high-@low)/@gap+(2*@row1)-i.rn,
N1 = (i.rn-@row1)*@gap+@low,
N2 = (i.rn-(@row1-1))*@gap+@low
FROM iTally AS i
ORDER BY i.rn
) AS r
WHERE @high&@low&@gap&@row1 IS NOT NULL AND @high >= @low AND @gap > 0;
GO
我相信这种方法简化了其他人提出的许多其他想法。它使用逐位算术和FOR XML
技巧以及CTE来生成二进制数字。
DECLARE @my_int INT = 5
;WITH CTE_Binary AS
(
SELECT 1 AS seq, 1 AS val
UNION ALL
SELECT seq + 1 AS seq, power(2, seq)
FROM CTE_Binary
WHERE
seq < 8
)
SELECT
(
SELECT
CAST(CASE WHEN B2.seq IS NOT NULL THEN 1 ELSE 0 END AS CHAR(1))
FROM
CTE_Binary B1
LEFT OUTER JOIN CTE_Binary B2 ON
B2.seq = B1.seq AND
@my_int & B2.val = B2.val
ORDER BY
B1.seq DESC
FOR XML PATH( )
) AS val
You can use a recursive CTE table to do this. In this example code, it is set for 16 bits, but you can do any length by changing 16-> your choice. Also, the data you want to convert is table DecimalTable
WITH DecimalTable AS (SELECT 10 decimal_num UNION SELECT 20),
DtoB AS (SELECT decimal_num
,1 n
,CAST(CAST(decimal_num%2 AS bit) AS VARCHAR(16)) binary_num
FROM DecimalTable
UNION ALL
SELECT decimal_num
,n*2 n
,CAST(CONCAT(CAST(decimal_num&n as bit), binary_num)
AS VARCHAR(16)) binary_num
FROM DtoB
WHERE n<POWER(2,16))
SELECT decimal_num, binary_num
FROM DtoB
此函数是一个通用转换器,允许将整数转换为任何基本编号系统的字符串描述,如二进制、八进制、十六进制等。
-- specify a string and numbering system Base value, for example 16 for hexadecimal
CREATE FUNCTION udf_IntToBaseXStr(@baseVal BIGINT,
@baseX BIGINT)
returns VARCHAR(63)
AS
BEGIN
--bigint : -2^63 (-9,223,372,036,854,775,808) to 2^63-1 (9,223,372,036,854,775,807)
-- or 63 ones (1111111,11111111,11111111,11111111,11111111,11111111,11111111,11111111) in binary
DECLARE @val BIGINT -- value from all
DECLARE @cv BIGINT -- value from a single char
DECLARE @baseStr VARCHAR(63)
SET @baseStr = ;
-- assumes a numbering method of 0123456789ABCDEF.....
SET @val = @baseVal
WHILE ( @val > 0 )
BEGIN
SET @cv = @val % @basex -- calculate the right most char s value
SET @baseStr = -- add it to (any existing) string
CASE
WHEN @cv < 10 THEN Char(Ascii( 0 ) + @cv)
ELSE Char(Ascii( A ) + ( @cv - 10 ))
END
+ @baseStr
SET @val = ( @val - @cv ) / @basex
END
RETURN @baseStr
END
GO
如果您需要保证最小长度,下一个函数会包装上面的函数,在前面加上一个ZEROES,迫使返回的字符串达到您想要的最小长度。它不会截断到指定的长度。
-- specify a string and numbering system Base value, for example, 16 for hexadecimal
-- prepends LEADING ZEROS to force length of returned string to be AT LEAST minLength chars
CREATE FUNCTION udf_IntToBaseXStr_MinLength(@baseVal BIGINT,
@baseX BIGINT,
@minLength INT)
returns VARCHAR(63)
AS
BEGIN
DECLARE @baseStr VARCHAR(63)
SET @baseStr = dbo.udf_IntToBaseXStr(@baseVal, @baseX)
IF Len(@baseStr) < @minLength
SET @baseStr = Replicate( 0 , @minLength - Len(@baseStr))
+ @baseStr
RETURN @baseStr
END
GO
udf_IntToBaseXStr用法:
;with CTE as
(
SELECT BaseX = 2, AKA = binary
UNION SELECT 8, octal
UNION SELECT 10, decimal
UNION SELECT 15, pentadecimal
UNION SELECT 16, hexadecimal
)
SELECT BaseX, AKA, Result = dbo.udf_IntToBaseXStr(328239523, BaseX) FROM CTE
udf_IntToBaseXStr结果:
BaseX | AKA | Result |
---|---|---|
2 | binary | 10011100100001000100110100011 |
8 | octal | 2344104643 |
10 | decimal | 328239523 |
15 | pentadecimal | 1DC3B24D |
16 | hexadecimal | 139089A3 |
udf_IntToBaseXStr_MinLength用法:
;with CTE as
(
SELECT BaseX = 2, AKA = binary
UNION SELECT 8, octal
UNION SELECT 10, decimal
UNION SELECT 15, pentadecimal
UNION SELECT 16, hexadecimal
)
SELECT BaseX, AKA, Result = dbo.udf_IntToBaseXStr_MinLength(328239523, BaseX, 24) FROM CTE
udf_IntToBaseXStr_MinLength结果:
BaseX | AKA | Result |
---|---|---|
2 | binary | 10011100100001000100110100011 |
8 | octal | 000000000000002344104643 |
10 | decimal | 000000000000000328239523 |
15 | pentadecimal | 00000000000000001DC3B24D |
16 | hexadecimal | 0000000000000000139089A3 |
想要轻松吗?做一些逐位计算来映射出每个二进制数字。
CREATE FUNCTION dbo.BinaryRep (@val INT)
RETURNS VARCHAR(32)
WITH EXECUTE AS CALLER
AS
BEGIN
DECLARE @ret VARCHAR(32)
DECLARE @cnt INT = 30; -- 30 to 0 inclusive in loop
-- handle negative (we re using signed magnitude because that s simple)
SET @ret = IIF(@val < 0, 1 , 0 );
SET @val = ABS(@val); -- totally cheating here.
-- bitwise masking madness, one digit at a time.
WHILE @cnt > -1
BEGIN
SET @ret = CONCAT(@ret, IIF(@val & POWER(2, @cnt) = 0, 0, 1));
SET @cnt = @cnt - 1;
END;
RETURN @ret;
END
唯一的转折点正是康斯坦丁注意到的:你觉得你的底片怎么样?
此版本价格低廉,使用有符号幅度,其中第一位为1
,表示负值,没有其他更改。-123
和123
仅因其高位不同。
select dbo.BinaryRep(123) as plus, dbo.BinaryRep(-123) as minus
plus minus
-------------------------------- --------------------------------
00000000000000000000000001111011 10000000000000000000000001111011
请注意,SQLServerINT
支持2-31到231,因此我们需要循环31次(包括30到0),而不是32次。
为什么不简单地。。。
declare @num int = 75
select
@num [Dec]
, convert (varchar(1), @num / 128 % 2)
+ convert (varchar(1), @num / 64 % 2)
+ convert (varchar(1), @num / 32 % 2)
+ convert (varchar(1), @num / 16 % 2)
+ convert (varchar(1), @num / 8 % 2)
+ convert (varchar(1), @num / 4 % 2)
+ convert (varchar(1), @num / 2 % 2)
+ convert (varchar(1), @num % 2) as [Bin]