Question: What is the mean huc example code when the example name's lower snake, there are 6 digits, and less than 3 levels?
SQL: SELECT AVG("Example code (HUC)") FROM "2-16087261-2" WHERE "Example name" = 'lower snake' AND "Digits" = 6.0 AND "Level" < 3.0;

Question: What's the approximate number of HUs when there are more than 2 digits, and 6 levels?
SQL: SELECT COUNT("Number of HUs (approximate)") FROM "2-16087261-2" WHERE "Digits" > 2.0 AND "Level" = 6.0;

Question: How many HUC example codes have 1 level?
SQL: SELECT COUNT("Example code (HUC)") FROM "2-16087261-2" WHERE "Level" = 1.0;

Question: What is the mean level number when the example name is Lower Snake and the approximate number is hus is less than 370?
SQL: SELECT AVG("Level") FROM "2-16087261-2" WHERE "Example name" = 'Lower Snake' AND "Number of HUs (approximate)" < 370.0;