What's this SQL doing?

Select c.clridx, n.price, n.perprice
from clr c, sprice_clrsku n where c.styleidx = 1164 and c.styleidx = c.styleidx and c.active = 1 and c.colouridx > 0 and n.spidx(+) = 163
and n.clridx(+) = c.clridx order by c.clrcode;

Notice the line "and c.styleidx = c.styleidx "? Why did the author set this SQL like this? Is this to accomplish something I do not know about?

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Julian Milano