documentclass{article}

usepackage{array}
usepackage[table]{xcolor}
usepackage{longtable}

% Before starting give a little space:
setlengthminrowclearance{2pt}

% This example shows rather poor taste but is quite colourful! Inspect the source
% file, colortbl.dtx, to see the full code for the example, but it uses the following
% column types.

newcolumntype{A}{%
    >{color{white}columncolor{red}[.5tabcolsep]%
        raggedright}%
    p{2cm}}

newcolumntype{B}{%
    >{columncolor{blue}[.5tabcolsep]%
        color{yellow}raggedright}
    p{3cm}}

newcolumntype{C}{%
    >{columncolor{yellow}[.5tabcolsep]}%
    D{.}{cdot}{3.3}}

newcolumntype{E}{%
    >{largebfseries
        columncolor{cyan}[.5tabcolsep]}c}

newcolumntype{F}{%
    >{color{white}
        columncolor{magenta}[.5tabcolsep]}c}

newcolumntype{G}{%
    >{columncolor[gray]{0.8}[.5tabcolsep][tabcolsep]}l}

newcolumntype{H}{>{columncolor[gray]{0.8}}l}

newcolumntype{I}{%
    >{columncolor[gray]{0.8}[tabcolsep][.5tabcolsep]}%
    D{.}{cdot}{3.3}}


begin{document}

% The code below is directly extracted from colortbl.dtx
% http://tug.ctan.org/macros/latex2e/contrib/colortbl/colortbl.dtx

begin{longtable}{ABC}
    multicolumn{3}{E}{A long table example}\
    multicolumn{2}{F}{First two columns}&
    multicolumn{1}{F}{Third column}\
    multicolumn{2}{F}{p-type}&
    multicolumn{1}{F}{D-type (textsf{dcolumn})}endfirsthead
    multicolumn{3}{E}{A long table example (continued)}\
    multicolumn{2}{F}{First two columns}&
    multicolumn{1}{F}{Third column}\
    multicolumn{2}{F}{p-type}&
    multicolumn{1}{F}{D-type (textsf{dcolumn})}endhead
    multicolumn{3}{E}{Continuedldots}endfoot
    multicolumn{3}{E}{The End}endlastfoot
    P-column&and another one&12.34\
    multicolumn{1}{G}{Total}&
    multicolumn{1}{H}{(wrong)}&
    multicolumn{1}{I}{100.6}\
    Some long text in the first column&bbb&1.2\
    aaa&and some long text in the second column&1.345\
    multicolumn{1}{G}{Total}&
    multicolumn{1}{H}{(wrong)}&
    multicolumn{1}{I}{100.6}\
    aaa&bbb&1.345\
    Note that the coloured rules in all columns stretch to accomodate
    arge entries in one column. &bbb&1.345\
    aaa&bbb&100\
    aaa&Depending on your driver you may get unsightly gaps or lines
    where the  `screens' used to produce different shapes interact
    badly. You may want to cause adjacent panels of the same colour by
    specifying a larger overhang
    or by adding some negative space (in a "noalign" between rows.&12.4\
    aaa&bbb&45.3\
end{longtable}


end{document}