SELECT count(distinct c) as nb FROM t_asv where b = 1 group by b
1 Now these are the generations of the sons of Noah, `namely', of Shem, Ham, and Japheth: and unto them were sons born after the flood. 2 The sons of Japheth: Gomer, and Magog, and Madai, and Javan, and Tubal, and Meshech, and Tiras. 3 And the sons of Gomer: Ashkenaz, and Riphath, and Togarmah. 4 And the sons of Javan: Elishah, and Tarshish, Kittim, and Dodanim. 5 Of these were the isles of the nations divided in their lands, every one after his tongue, after their families, in their nations. 6 And the sons of Ham: Cush, and Mizraim, and Put, and Canaan. 7 And the sons of Cush: Seba, and Havilah, and Sabtah, and Raamah, and Sabteca; and the sons of Raamah: Sheba, and Dedan. 8 And Cush begat Nimrod: he began to be a mighty one in the earth. 9 He was a mighty hunter before Jehovah: wherefore it is said, Like Nimrod a mighty hunter before Jehovah. 10 And the beginning of his kingdom was Babel, and Erech, and Accad, and Calneh, in the land of Shinar. 11 Out of that land he went forth into Assyria, and builded Nineveh, and Rehoboth-ir, and Calah, 12 and Resen between Nineveh and Calah (the same is the great city). 13 And Mizraim begat Ludim, and Anamim, and Lehabim, and Naphtuhim, 14 and Pathrusim, and Casluhim (whence went forth the Philistines), and Caphtorim. 15 And Canaan begat Sidon his first-born, and Heth, 16 and the Jebusite, and the Amorite, and the Girgashite, 17 and the Hivite, and the Arkite, and the Sinite, 18 and the Arvadite, and the Zemarite, and the Hamathite: and afterward were the families of the Canaanite spread abroad. 19 And the border of the Canaanite was from Sidon, as thou goest toward Gerar, unto Gaza; as thou goest toward Sodom and Gomorrah and Admah and Zeboiim, unto Lasha. 20 These are the sons of Ham, after their families, after their tongues, in their lands, in their nations. 21 And unto Shem, the father of all the children of Eber, the elder brother of Japheth, to him also were children born. 22 The sons of Shem: Elam, and Asshur, and Arpachshad, and Lud, and Aram. 23 And the sons of Aram: Uz, and Hul, and Gether, and Mash. 24 And Arpachshad begat Shelah; and Shelah begat Eber. 25 And unto Eber were born two sons: The name of the one was Peleg. For in his days was the earth divided. And his brother's name was Joktan. 26 And Joktan begat Almodad, and Sheleph, and Hazarmaveth, and Jerah, 27 and Hadoram, and Uzal, and Diklah, 28 and Obal, and Abimael, and Sheba, 29 and Ophir, and Havilah, and Jobab: all these were the sons of Joktan. 30 And their dwelling was from Mesha, as thou goest toward Sephar, the mountain of the east. 31 These are the sons of Shem, after their families, after their tongues, in their lands, after their nations. 32 These are the families of the sons of Noah, after their generations, in their nations: and of these were the nations divided in the earth after the flood.