Question: On which date was the opponent Lamine Ouahab?
SQL: SELECT "Date" FROM "2-18042031-15" WHERE "Opponent" = 'Lamine Ouahab';

Question: On what date did the match take place in a round of 1R and have a result 2–6, 5–7, 2–6?
SQL: SELECT "Date" FROM "2-18042031-15" WHERE "Round" = '1R' AND "Result" = '2–6, 5–7, 2–6';

Question: What is the result of the match in round 1R against Tunisia and on a Hard surface?
SQL: SELECT "Result" FROM "2-18042031-15" WHERE "Round" = '1R' AND "Surface" = 'Hard' AND "Against" = 'Tunisia';

Question: Who was the match against when on a Clay surface during round 2R?
SQL: SELECT "Against" FROM "2-18042031-15" WHERE "Round" = '2R' AND "Surface" = 'Clay';

Question: What round had a amtch against Cyprus and an edition of 2010 Davis Cup Europe/Africa Group II?
SQL: SELECT "Round" FROM "2-18042031-15" WHERE "Edition" = '2010 Davis Cup Europe/Africa Group II' AND "Against" = 'Cyprus';