how to join sql tables in my desired way - sql-server

Question

I have 2 sql tables named mtblAttendance and mtblLeave_Data.
I need to get the all dates from mtblLeave_Data when User was on leave depending on absent in mtblAttendance.
In my mtblAttendance for every leave there is a row, but if a user on leave for a period so there is no unique row, there are just two columns Leave_From and Leave_To (or it may be a single entry where Leave_From= Leave_To).
For getting the absent dates of user I wrote the query
USE [ILeave]
ALTER procedure [dbo].[Attendance_Report]
#Date1 datetime,
#Date2 datetime,
#User_Id nvarchar(50)
as begin
SELECT distinct
a.Sno,
a.[Login_Date],
a.[Week_Day],
a.[In_Time],
a.[Out_Time],
a.Attendance_Status,
a.Half_Full,
a.Leave_Type,
(convert(varchar(max),floor (abs(cast(datediff(mi, a.Out_Time, a.In_Time) AS int) / 60)))+ '.'+ convert(varchar(max),(abs(cast(datediff(mi, a.Out_Time, a.In_Time) AS int) % 60)))) as Hrs
, l.[Sno]
, l.[Leave_ID]
, l.[User_Id]
, l.[Dept_To]
, l.[Leave_Type]
, l.[Total_Leave_HR]
, l.[Leave_From]
, l.[Leave_To]
, l.[Leave_Half_Full]
, l.[Comments]
, l.[Leave_Status]
FROM
[mtblAttendance] a
LEFT JOIN [mtbl_Leave_Data] l
ON a.[Login_Date] BETWEEN l.[Leave_From] AND l.[Leave_To]
AND l.[User_Id] = a.[User_Id] where a.Login_Date between #Date1 and #Date2 and a.User_Id=#User_Id order by Login_Date
end

Answer 1

The following query should return the leave record assigned
SELECT
a.[Login_Date]
, l.[Sno]
, l.[Leave_ID]
, l.[User_Id]
, l.[Dept_To]
, l.[Leave_Type]
, l.[Total_Leave_HR]
, l.[Leave_From]
, l.[Leave_To]
, l.[Leave_Half_Full]
, l.[Comments]
, l.[Leave_Status]
FROM
[mtblAttendance] a
LEFT JOIN [mtbl_Leave_Data] l ON a.[Login_Date] BETWEEN l.[Leave_From] AND l.[Leave_To]
WHERE
a.User_Id = 'sasi'
AND a.Attendance_Status='A'
I put it into a fiddle, but with no data so all I can say is that the query parses.
As someone has previously stated, it is common to have tables with dates in, whereby queries requiring every date in a 2 year period can quickly be assessed.
Updated SQL:
SELECT DISTINCT
a.[Login_Date]
, l.[Sno]
, l.[Leave_ID]
, l.[User_Id]
, l.[Dept_To]
, l.[Leave_Type]
, l.[Total_Leave_HR]
, l.[Leave_From]
, l.[Leave_To]
, l.[Leave_Half_Full]
, l.[Comments]
, l.[Leave_Status]
FROM
[mtblAttendance] a
LEFT JOIN [mtbl_Leave_Data] l
ON a.[Login_Date] BETWEEN l.[Leave_From] AND l.[Leave_To]
AND l.[userId] = a.[user_id] -- Ensure only attendance/leave for the same user being linked
WHERE
a.User_Id = 'sasi'
AND a.Attendance_Status='A'

Answer 2

Join expressions aren't limited to using the equals sign. Use "between" in the join expression. Something along these (untested) lines should work.
select distinct A.Login_Date
from mtblAttendance A
inner join mtbl_Leave_Data L
on A.User_id = L.User_id
and A.Login_date between L.Leave_From and L.Leave_To
where A.User_Id = 'sasi' AND A.Attendance_Status='A'
Depending on what you're trying to do, you might need to change the inner join to a left outer join. A left outer join will preserve all login dates from mtblAttendance, regardless of whether they satisfy the join condition. (Those rows will be filtered by the WHERE clause, of course.)