I don't know why this happen in longtable its generated extra row at the bottom of the table which is unwanted row, Please somebody help me to solved this problem here is my MWE
\documentclass[10pt,a4paper]{article}
\usepackage[left=0.5cm]{geometry}
\usepackage{datatool}
\usepackage{filecontents}
\usepackage{siunitx}
\usepackage[all]{tcolorbox}
\usepackage{graphicx,booktabs,xstring,datatool,xintexpr,longtable} %for including eps graphics
\usepackage{multirow,colortbl,xfp}
\begin{filecontents}{data.csv}
ID,Name,January,February,March,April,May,June,July,August,September,October,November,December
ABC01,Mr. ABC,1,3432,54,54,54,56,54,54,54,54,54,54.25
ABC02,Mr. ABC,2,354,234,234,234,80,234,234,234,234,234,234
ABC03,Mr. ABC,1,544,343,343,343,0,343,343,343,343,343,343
ABC04,Mr. ABC,0,3423,343,343,0,0,343,343,343,343,343,343
ABC05,Mr. ABC,1,34,434,434,0,0,434,434,434,434,434,434
ABC06,Mr. ABC,2,0,42,42,0,0,42,42,42,42,42,42
ABC07,Mr. ABC,25,0,3432,3432,0,0,3432,3432,3432,3432,3432,3432
ABC08,Mr. ABC,23,0,343,343,343,0,343,343,343,343,343,343
ABC09,Mr. ABC,12,0,43,43,43,0,43,43,43,43,43,43
ABC10,Mr. ABC,0,0,90,90,90,0,90,90,90,90,90,90
,Mr. ABC,34,0,0,0,0,0,0,0,0,0,0,0
,Mr. ABC,44,12,0,0,0,0,0,0,0,0,0,0
\end{filecontents}
\newcounter{Serial}
\newcounter{SerialN}
\DTLloaddb{name}{data.csv}
\begin{document}
\centering
\edef\numberofrows{\DTLrowcount{name}}%
\DTLsumcolumn{name}{January}{\JanT}
\DTLsumcolumn{name}{February}{\FebT}
\DTLsumcolumn{name}{March}{\MarT}
\DTLsumcolumn{name}{April}{\AprT}
\DTLsumcolumn{name}{May}{\MayT}
\DTLsumcolumn{name}{June}{\JunT}
\DTLsumcolumn{name}{July}{\JulT}
\DTLsumcolumn{name}{August}{\AugT}
\DTLsumcolumn{name}{September}{\SepT}
\DTLsumcolumn{name}{October}{\OctT}
\DTLsumcolumn{name}{November}{\NovT}
\DTLsumcolumn{name}{December}{\DecT}
\begin{longtable}{|c|l|c|c|c|c|c|c|c|c|c|c|c|c|c|}
\hline
\rowcolor{green!20}\bf\rotatebox{90}{\hspace*{1mm}Sl.~No.} & \bf{\raisebox{3.5ex}{Name}} & \bf\rotatebox{90}{January}& \bf\rotatebox{90}{February}& \bf\rotatebox{90}{March} & \bf\rotatebox{90}{April}&\bf\rotatebox{90}{May} & \bf\rotatebox{90}{June} & \bf\rotatebox{90}{July} & \bf\rotatebox{90}{August} & \bf\rotatebox{90}{September}& \bf\rotatebox{90}{October} & \bf\rotatebox{90}{November} & \bf\rotatebox{90}{December}& \bf{\raisebox{4ex}{Total}}\\\hline \endhead
\DTLforeach*{name}{\name=Name,\jan=January,\feb=February,\mar=March,\apr=April,\may=May,\jun=June,\jul=July,\aug=August,\sep=September,\oct=October,\nov=November,\dec=December,\id=ID}{% build table
\IfSubStr{\id}{DBC}{\stepcounter{Serial}}{}
\IfInteger{\theSerial}{\stepcounter{SerialN}}{}
\theSerialN &\name&\jan&\feb&\mar&\apr&\may&\jun&\jul&\aug&\sep&\oct&\nov&\dec&\\\hline
}\\\bottomrule
\multicolumn{2}{|c|}{\it Total} & \JanT&\FebT&\MarT&\AprT&\MayT&\JunT&\JulT&\AugT&\SepT&\OctT&\NovT&\DTLtrunc{\result}{\DecT}{2}\result& \\ \hline
\end{longtable}
\end{document}

\\before your first\bottomruleand that as well. – TeXnician May 18 '17 at 08:18