Calculate difference between Dates in SQL Server, with Years, Months, and Days output

SQL

CREATE TABLE [tablexemplo](
    [DataAdmissao] [date] NULL
) ON [PRIMARY];

INSERT INTO tablexemplo values('2010-01-30');
INSERT INTO tablexemplo values('2010-02-28');
INSERT INTO tablexemplo values('2010-03-30');
INSERT INTO tablexemplo values('2010-06-29');
INSERT INTO tablexemplo values(GetDate());

SQL

SELECT 
    DataAdmissao,
    CASE WHEN Mes < 0 THEN
        (Ano - 1)   
    ELSE
        Ano
    END as Ano,
    CASE WHEN Mes < 0 THEN
        (Mes + 12)  
    ELSE
        Mes
    END as Mes,
    Dia
FROM (
    SELECT 
        DataAdmissao, 
        Ano, 
        CASE WHEN Dia < 0 THEN
            (Dia + 30)  
        ELSE
            Dia
        END as Dia,
        CASE WHEN Dia < 0 THEN
            (Mes - 1)   
        ELSE
            Mes
        END as Mes
    FROM (
        SELECT DataAdmissao, 
            (YEAR(GETDATE()) - YEAR(DataAdmissao)) as Ano,
            (MONTH(GETDATE()) - MONTH(DataAdmissao)) as Mes,
            (DAY(GETDATE()) - DAY(DataAdmissao)) as Dia
        FROM tablexemplo 
        ) AS T
    )T1 

Example: SQLFiddle / a>

I've adapted the other answer solution:

SELECT
   DataAdmissao,
   Hoje,
   YEAR( Tempo ) - 1 AS Anos,
   MONTH( Tempo ) - 1 AS Meses,
   DAY( Tempo ) - 1 AS FCCDias

FROM (
  SELECT
     DataAdmissao,
     CAST( GetDate() AS date ) AS Hoje,
     DATEADD( day, -DAY( DataAdmissao ) + 1,
        DATEADD( month, -MONTH( DataAdmissao ) + 1,
           DATEADD( year, -YEAR( DataAdmissao ) + 1,
              CAST( GetDate() AS date )
           )
        )
     ) AS Tempo FROM TabelaExemplo
  ) AS T;

For more details, click here and read the comments left.

  

See working in SQL Fiddle

I have formatted a query to list the correct results, always considering the correct differences between months and days as well.

DECLARE @DifDataIn as datetime, @DifDataFi as datetime
SET @DifDataIn = '1988-12-22'
SET @DifDataFi = '2015-11-27'

SELECT 
    -- Cálculo dos Anos
    Case
        When  month(@DifDataIn) < month(@DifDataFi) or
            ( month(@DifDataIn) = month(@DifDataFi) and day(@DifDataIn) <= day(@DifDataFi) )
            THEN datediff(year,@DifDataIn,@DifDataFi)
        Else 
            Case
                When year(@DifDataIn) = year(@DifDataFi) then 0
                Else datediff(year,@DifDataIn,@DifDataFi) - 1
            End
    End as ANOS,
    -- Cálculo dos Meses
    Case
        When day(@DifDataFi) >= day(@DifDataIn) then
            datediff(month,@DifDataIn,@DifDataFi) - (floor(datediff(month,@DifDataIn,@DifDataFi) /12) * 12)
        Else
            datediff(month,@DifDataIn,@DifDataFi) - (floor(datediff(month,@DifDataIn,@DifDataFi) /12) * 12) -1
    End as MESES,
    -- Cálculo dos Dias
    Case
        When day(@DifDataFi) >= day(@DifDataIn) then day(@DifDataFi) - day(@DifDataIn)
        Else datediff(day, ( cast(year(@DifDataFi) as varchar(4)) +'-'+ cast(month(@DifDataFi)-1 as varchar(2)) +'-'+ cast(day(@DifDataIn) as varchar(2)) ),
                           ( cast(year(@DifDataFi) as varchar(4)) +'-'+ cast(month(@DifDataFi)   as varchar(2)) +'-'+ cast(day(@DifDataFi) as varchar(2)) )
                     )
    End as DIAS