Hacking web site or database passing some sql and some code through URL

Hi,

Some one is try to hack my web sitte by passing some sql and some code through my URL,  These are the some attemts i got from my costom log file


?showimage=') UNION SELECT 'pixelpost_15rc1.nasl-1233433052.jpg' as id, 1326874612 as headline, 1713086692 as datetime, 223249252 as body, 813970374 as category, 1978864233 as image