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Editorial Team
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Asked: 2026-05-13T09:59:35+00:00

I have a table with a DATE column with time (as usual in Oracle

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I have a table with a DATE column with time (as usual in Oracle since there isn’t a TIME type). When I query that column from JDBC, I have two options:

  • Manually convert the values with Oracle’s to_date()
  • Use a java.sql.Timestamp

Both approaches work and have exclusive areas of hideousness. My problem is when I’m SELECTing data. Here are two sample queries:

select *
from TABLE
where TS between {ts '2009-12-08 00:00:00.000'} and {ts '2009-12-09 00:00:00.000'}

select *
from TABLE
where TS between trunc({ts '2009-12-08 00:00:00.000'}) and trunc({ts '2009-12-09 00:00:00.000'})

Both queries work, return the same results and produce the exact same output in EXPLAIN PLAN. This right indexes are used.

Only query one runs 15 minutes while the second query takes 0.031s. Why is that? Is there a central place to fix this or do I have to check all my queries for this column and make utterly sure that the trunc() is in there? How do I fix this issue when I need to select down to a certain second?

[EDIT] The table is partitioned and I’m on Oracle 10.2.0.

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1 Answer

  1. Editorial Team

    I don’t understand what {ts ‘2009-12-08 00:00:00.000’} actually mean, since this isn’t Oracle SQL as far as I know. Can you show exactly what the query is you’re running?

    One possible problem is that you’re specifying your range with milliseconds. Oracle’s DATE type only goes down to seconds. (Use TIMESTAMP type if you need to store fractions of seconds). But what might be happening is that in the first query, Oracle is converting each DATE value to a TIMESTAMP in order to do the comparison to your specified TIMESTAMP.
    In the second case, it knows TRUNC() will effectively round your value to something that can be expressed as a DATE, so no conversion is needed.

    If you want to avoid such implicit conversions, make sure you’re always comparing like with like.
    eg

    select * 
from my_table t
where t.ts between to_date('2009-12-08','YYYY-MM-DD') and to_date('2009-12-09','YYYY-MM-DD')
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