col : rank | nation | gold | silver | bronze | total row 1 : 1 | chinese taipei (tpe) | 2 | 0 | 0 | 2 row 2 : 1 | russia (rus) | 2 | 0 | 0 | 2 row 3 : 3 | great britain (gbr) | 1 | 0 | 0 | 1 row 4 : 4 | slovakia (svk) | 0 | 2 | 2 | 4 row 5 : 5 | china (chn) | 0 | 2 | 1 | 3 row 6 : 6 | mexico (mex) | 0 | 1 | 1 | 2 row 7 : 7 | germany (ger) | 0 | 0 | 2 | 2 row 8 : 8 | south korea (kor) | 0 | 0 | 1 | 1 row 9 : 8 | switzerland (sui) | 0 | 0 | 1 | 1 row 10 : 8 | thailand (tha) | 0 | 0 | 1 | 1 row 11 : 8 | uzbekistan (uzb) | 0 | 0 | 1 | 1
how many nations are shown? of those which have silver medals? which of those only has one silver medal?
mexico (mex)
Rank Nation Gold Silver Bronze Total
which of those only has one silver medal?
1 Chinese Taipei (TPE) 2 0 0 2
1 Russia (RUS) 2 0 0 2
3 Great Britain (GBR) 1 0 0 1
4 Slovakia (SVK) 0 2 2 4
5 China (CHN) 0 2 1 3
6 Mexico (MEX) 0 1 1 2
7 Germany (GER) 0 0 2 2
8 South Korea (KOR) 0 0 1 1
8 Switzerland (SUI) 0 0 1 1
8 Thailand (THA) 0 0 1 1
8 Uzbekistan (UZB) 0 0 1 1
Mexico (MEX)
which of those only has one silver medal? || of those which have silver medals? | how many nations are shown?