=?UTF-8?B?6rmA66qF7KSA?= <audwns525@xxxxxxxxx> writes: > explain analyze > SELECT * FROM users WHERE name = 'User '||trunc(random()*100) ; > I expected the result to return one record. However, in some cases, the > result comes back with 2 or 3 records. What am I doing wrong? random() is re-evaluated at each row, so it's not that surprising if you sometimes get multiple matches. This is the same behavior that you relied on to fill the table with not-all-the-same names. The preferred way to avoid that is to stuff the random() call into a CTE: WITH x AS (SELECT random() AS r) SELECT * FROM users, x WHERE name = 'User '||trunc(r*100) ; or in this case better to shove the whole constant computation into the CTE. regards, tom lane
