SELECT count(distinct c) as nb FROM t_asv where b = 16 group by b
1 The words of Nehemiah the son of Hacaliah. Now it came to pass in the month Chislev, in the twentieth year, as I was in Shushan the palace, 2 that Hanani, one of my brethren, came, he and certain men out of Judah; and I asked them concerning the Jews that had escaped, that were left of the captivity, and concerning Jerusalem. 3 And they said unto me, The remnant that are left of the captivity there in the province are in great affliction and reproach: the wall of Jerusalem also is broken down, and the gates thereof are burned with fire. 4 And it came to pass, when I heard these words, that I sat down and wept, and mourned certain days; and I fasted and prayed before the God of heaven, 5 and said, I beseech thee, O Jehovah, the God of heaven, the great and terrible God, that keepeth covenant and lovingkindness with them that love him and keep his commandments: 6 Let thine ear now be attentive, and thine eyes open, that thou mayest hearken unto the prayer of thy servant, which I pray before thee at this time, day and night, for the children of Israel thy servants while I confess the sins of the children of Israel, which we have sinned against thee. Yea, I and my father's house have sinned: 7 we have dealt very corruptly against thee, and have not kept the commandments, nor the statutes, nor the ordinances, which thou commandedst thy servant Moses. 8 Remember, I beseech thee, the word that thou commandedst thy servant Moses, saying, If ye trespass, I will scatter you abroad among the peoples: 9 but if ye return unto me, and keep my commandments and do them, though your outcasts were in the uttermost part of the heavens, yet will I gather them from thence, and will bring them unto the place that I have chosen, to cause my name to dwell there. 10 Now these are thy servants and thy people, whom thou hast redeemed by thy great power, and by thy strong hand. 11 O Lord, I beseech thee, let now thine ear be attentive to the prayer of thy servant, and to the prayer of thy servants, who delight to fear thy name; and prosper, I pray thee, thy servant this day, and grant him mercy in the sight of this man. Now I was cupbearer to the king.