2008-09-24 28 views

Respuesta

15

Lo siguiente podría codificarse en una función. Debería recortar los ceros a la izquierda para cumplir con los requisitos de su pregunta.

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)[email protected] 
    select @intvalue = convert(int, (@intvalue/2)), @[email protected] 
    end 
select @vsresult 
+1

Esta es una muy mala solución. (1) No es necesario utilizar ningún bucle (2), no es necesario realizar cálculos matemáticos complejos, como calcular el módulo para cada potencia 2. Puede consultar este blog breve para obtener una solución mucho mejor basada en BITWISE: http: // ariely .info/Blog/tabid/83/EntryId/169/T-SQL-Converting-between-Decimal-Binary-and-Hexadecimal.aspx –

2
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 
1
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); 
+0

creo que la última línea de su código podría ser cambiado a SELECT FinalBin DE DONDE ComputeBin intval = 1 El min debe ser siempre en este código. Además, este código solo funciona para números positivos, FYI. – Kevin

12

En realidad esto es muy simple utilizando SQL llanura de edad. Solo use ANDs bit a bit. Me sorprendió un poco que no haya una solución simple publicada en línea (que no haya invocado UDF). En mi caso, realmente quería verificar si los bits estaban activados o desactivados (los datos provienen de dotnet eNums).

En consecuencia aquí es un ejemplo que le dará por separado y juntos - valores de bit y cadena binaria (la gran unión es sólo una manera hacky de producir números que trabajar al otro lado de DB:

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 

Produce este resultado :

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 
+0

+1 para una expresión que puedo usar como columna calculada – Gabe

0

¿Qué tal esto ...

SELECT number_value 
,MOD(number_value/32768, 2) AS BIT15 
,MOD(number_value/16384, 2) AS BIT14 
,MOD(number_value/8192, 2) AS BIT13 
,MOD(number_value/4096, 2) AS BIT12 
,MOD(number_value/2048, 2) AS BIT11 
,MOD(number_value/1024, 2) AS BIT10 
,MOD(number_value/ 512, 2) AS BIT9 
,MOD(number_value/ 256, 2) AS BIT8 
,MOD(number_value/ 128, 2) AS BIT7 
,MOD(number_value/ 64, 2) AS BIT6 
,MOD(number_value/ 32, 2) AS BIT5 
,MOD(number_value/ 16, 2) AS BIT4 
,MOD(number_value/ 8, 2) AS BIT3 
,MOD(number_value/ 4, 2) AS BIT2 
,MOD(number_value/ 2, 2) AS BIT1 
,MOD(number_value  , 2) AS BIT0 
FROM your_table; 
+0

MOD no es sqlserver –

0

creo que t su método simplifica muchas de las otras ideas que otros han presentado. Utiliza la aritmética bit a bit junto con el truco FOR XML con un CTE para generar los dígitos binarios.

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 
0

que utilizó la siguiente ITVF función para convertir de decimal a binario ya que es una función en línea que no es necesario "preocupación" acerca de varias lecturas realizadas por el optimizador.

 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*/ 
0
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 

Standard SQL (probado en PostgreSQL).

0

En SQL Server, puede intentar algo como el ejemplo siguiente:

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 
1

Aquí hay un poco de un cambio en el accepted answer from Sean, ya que me pareció que limita a sólo permiten un número codificado de dígitos en la salida . En mi uso diario, me resulta más útil obtener solo hasta el 1 dígito más alto o especificar cuántos dígitos estoy esperando. Automáticamente rellenará el lado con 0s, de modo que se alinee a 8, 16 o cualquier cantidad de bits que desee.

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; 
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