T-sql store PROC explanation

Question

create table #chartData(
ChgText [varchar](500) NOT NULL,
ChgCount [int] NULL,
[Sort] [int] NOT NULL,
[PartcTot] [int] NULL,
PercentageOfTotal decimal(6,3)
declare @partcTot int;
declare @SQLString nvarchar(4000), @ParamDefinition nvarchar(500);
declare @NewLine char(2)
select @partcTot = [frdmrpt].[fn_pha_total_participants](default);
set @NewLine=char(13)+char(10)
set @SQLString =
N'insert into #chartData (ChgText,ChgCount,Sort,PartcTot,PercentageOfTotal)' + @NewLine
set @SQLString = @SQLString +
N'select t.ChgText, c.TypeCount, t.Sort, ' + cast(@partcTot as nvarchar) + N' as PartcTot, (frdmrpt.fn_pha_percent(c.TypeCount,'
set @SQLString = @SQLString +
cast(@partcTot as nvarchar) + N')/100.0) as PercentageOfTotal' + @NewLine
set @SQLString = @SQLString +
N'from [frdmrpt].[wt_rpt_pha_pw_Rdy2ChgLevels] t inner join (' + @NewLine
set @SQLString = @SQLString +
N' select d.' + @HRADetail_Column + N' as ChgType, COUNT(*) as TypeCount' + @NewLine
set @SQLString = @SQLString +
N' from [frdmrpt].[wt_rpt_pha_pw_Member] m join [frdmrpt].[wt_rpt_pha_pw_HRADetail2] d on d.UserID = m.UserID' + @NewLine
set @SQLString = @SQLString +
N' group by d.' + @HRADetail_Column + @NewLine
set @SQLString = @SQLString +
N') c on t.ChgType = lower(c.ChgType) order by t.Sort' + @NewLine
--print @SQLString;
exec sp_executesql @SQLString;
select ChgText,ChgCount,Sort,PartcTot,PercentageOfTotal from #chartData
end
GO
Can someone explain the code to me using comment especially what is going on in the
set @SQLString =

Answer 1

-- @partcTot value will be computed by function - [fn_pha_total_participants]
SELECT @partcTot = [frdmrpt].[fn_pha_total_participants](DEFAULT);
--Below statments will form a SQL INSERT statement into @SQLString
-- @NewLine variable will act as new line/pressing Enter key. That is why @NewLine is used at the end of line in below statements
SET @NewLine = CHAR(13) + CHAR(10)
-- Below will form INSERT INTO Table(<<ColumnList>>) statement
SET @SQLString = N'insert into #chartData (ChgText,ChgCount,Sort,PartcTot,PercentageOfTotal)' + @NewLine
-- PercentageOfTotal column is calculated here
SET @SQLString = @SQLString + N'select t.ChgText, c.TypeCount, t.Sort, ' + cast(@partcTot AS NVARCHAR) + N' as PartcTot, (frdmrpt.fn_pha_percent(c.TypeCount,'
SET @SQLString = @SQLString + cast(@partcTot AS NVARCHAR) + N')/100.0) as PercentageOfTotal' + @NewLine
-- wt_rpt_pha_pw_Rdy2ChgLevels table has inner join with table - (wt_rpt_pha_pw_Member which has self join again)
SET @SQLString = @SQLString + N'from [frdmrpt].[wt_rpt_pha_pw_Rdy2ChgLevels] t inner join (' + @NewLine
SET @SQLString = @SQLString + N' select d.' + @HRADetail_Column + N' as ChgType, COUNT(*) as TypeCount' + @NewLine
SET @SQLString = @SQLString + N' from [frdmrpt].[wt_rpt_pha_pw_Member] m join [frdmrpt].[wt_rpt_pha_pw_Member] d on d.UserID = m.UserID' + @NewLine
SET @SQLString = @SQLString + N' group by d.' + @HRADetail_Column + @NewLine
SET @SQLString = @SQLString + N') c on t.ChgType = lower(c.ChgType) order by t.Sort' + @NewLine
-- Uncomment below print statement to see what is your final SQL statement formed
-- print @SQLString;
-- Above SQLString is executed and data is inserted into #chartData
EXEC sp_executesql @SQLString;
-- At the end your SP selects the data from #chartData
SELECT ChgText
, ChgCount
, Sort
, PartcTot
, PercentageOfTotal
FROM #chartData
GO
-- You also need to declare @HRADetail_Column variable
-Vaibhav Chaudhari