Question

I have an sql query in which I need to select the records from table where the time is between 3:00 PM yesterday to 3:00 PM today if today’s time is more than 3:00 PM.

If today’s time is less than that, like if today’s time is 1:00 PM. then then my query should take today’s time as 1:00 PM (which should return me records).

I need to get the time between 3:00pm yesterday to 3:00pm today if todays time is more than 3:00pm
if todays time is less than 3:00pm then get the 3:00pm yesterday to current time today

Answer 1

The best way of handling this is to use an IF statement:

IF TO_CHAR(SYSDATE, 'HH24') >= 15 THEN 

  SELECT x.*
    FROM YOUR_TABLE x
   WHERE x.date_column BETWEEN TO_DATE(TO_CHAR(SYSDATE -1, 'YYYY-MM-DD')|| ' 15:00:00', 'YYYY-MM-DD HH24:MI:SS')
                           AND TO_DATE(TO_CHAR(SYSDATE, 'YYYY-MM-DD')|| ' 15:00:00', 'YYYY-MM-DD HH24:MI:SS')

ELSE

  SELECT x.*
    FROM YOUR_TABLE x
   WHERE x.date_column BETWEEN TO_DATE(TO_CHAR(SYSDATE -1, 'YYYY-MM-DD')|| ' 15:00:00', 'YYYY-MM-DD HH24:MI:SS')
                           AND SYSDATE

END IF;

Conditional WHERE clauses are non-sargable.

Previously:

If I understand correctly, you want to get records within the last day. If the current time is 3 PM or later, the time should be set to 3 PM. If earlier than 3 PM, take the current time…

SELECT x.*
  FROM YOUR_TABLE x
  JOIN (SELECT CASE
                 WHEN TO_CHAR(SYSDATE, 'HH24') >= 15 THEN 
                  TO_DATE(TO_CHAR(SYSDATE, 'YYYY-MM-DD')|| ' 15:00:00', 'YYYY-MM-DD HH24:MI:SS')
                 ELSE SYSDATE
               END AS dt
          FROM DUAL) y ON x.date_column BETWEEN dt - 1 AND dt

Note:

dt - 1 means that 24 hours will be subtracted from the Oracle DATE.

Reference:

• TO_CHAR
• TO_DATE