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SELECT *

FROM table

WHERE (

CASE

WHEN condition1 = 'xxx'

THEN 1

ELSE 0

END + CASE

WHEN condition2 = 'xxx'

THEN 1

ELSE 0

END + CASE

WHEN condition3 = 'xxx'

THEN 1

ELSE 0

END + CASE

WHEN condition4 = 'xxx'

THEN 1

ELSE 0

END + CASE

WHEN condition5 = 'xxx'

THEN 1

ELSE 0

END + CASE

WHEN condition6 = 'xxx'

THEN 1

ELSE 0

END + CASE

WHEN condition7 = 'xxx'

THEN 1

ELSE 0

END + CASE

WHEN condition8 = 'xxx'

THEN 1

ELSE 0

END + CASE

WHEN condition9 = 'xxx'

THEN 1

ELSE 0

END + CASE

WHEN condition10 = 'xxx'

THEN 1

ELSE 0

END

) >= 8