CREATE TABLE useracct (name VARCHAR, u_id VARCHAR)
CREATE TABLE trust (target_u_id VARCHAR)

Find the name of the target user with the lowest trust score.
SELECT T1.name FROM useracct AS T1 JOIN trust AS T2 ON T1.u_id = T2.target_u_id ORDER BY trust LIMIT 1
SELECT "T1"."name" FROM "useracct" AS "T1" JOIN "trust" AS "T2" ON "T1"."u_id" = "T2"."target_u_id" ORDER BY "trust" NULLS FIRST LIMIT 1