user: Question: What chng has a rank greater than 6, with 12 as a prev?
Columns: ['Rank', 'Prev', 'Player', 'Rating', 'Chng']
Types: ['real', 'real', 'text', 'real', 'text']
Sample row: [1.0, 2.0, 'Viswanathan Anand ( IND )', 2803.0, '+4']
SQL:

assistant: SELECT "Chng" FROM "Table" WHERE "Rank" > 6.0 AND "Prev" = 12.0;