In the below query I want to add an AND condition inside the CASE\'s WHEN and before THEN is that possible?
for example WHEN \'r\' AND table1.name=\"jones\" THEN \'very
You can rewrite your statement like this to accomplish what you want
SELECT table1.id, table1.name,
CASE
WHEN table1.event = 'r' AND table1.name = 'jones' THEN 'very high'
WHEN table1.event = 't' AND table1.name = 'smith' THEN 'very low'
ELSE (SELECT table2.risk FROM table2 WHERE table2.value <= table1.value
ORDER BY table2.value DESC LIMIT 1)
END AS risk
FROM table1
ORDER BY FIELD( table1.event, 'r', 'f', 't' ), table1.value DESC
notice that you need to remove table1.event
after the CASE
statement.
documentation here