How to check date in postgresql

Question

my table name is tbl1 . The fileds are id , name , txdate .

| ID | NAME    | TXDATE    |
| 1  | RAJ     | 1-1-2013  |
| 2  | RAVI    |           |
| 3  | PRABHU  | 25-3-2013 |
| 4  | SAT     |           |

Now i want to use select query for check txdate < 2-2-2013 in which rows have txdate not empty and the select also retrun which rows have txdate empty.

The Result is like this

| ID | NAME    | TXDATE    |
| 1  | RAJ     | 1-1-2013  |
| 2  | RAVI    |           |
| 4  | SAT     |           |

Any feasible solution is there?. With out using union it is possible?.

Answer 1

I don't now what database your are using and what data type the TXDATE is.

I just tried on my postgreSQL 9.2, with a field "timestamp without time zone".

I have three rows in the table , like:

 ac_device_name | ac_last_heartbeat_time

----------------+-------------------------

 Nest-Test1     |

 Nest-Test3     |

 Nest-Test2     | 2013-04-10 15:06:18.287

Then use below statement

select ac_device_name,ac_last_heartbeat_time 
from at_device 
where ac_last_heartbeat_time<'2013-04-11';

It is ok to return only one record:

 ac_device_name | ac_last_heartbeat_time

----------------+-------------------------

 Nest-Test2     | 2013-04-10 15:06:18.287

I think you can try statement like:

select * from tbl1 where TXDATE<'2-2-2013' and TXDATE is not NULL

this statement also works in my environment.

Answer 2

Assuming that the TXDATE is of data type DATE then you can use WHERE "TXDATE" < '2013-2-2' OR "TXDATE" IS NULL . Something like:

SELECT *
FROM table1
WHERE "TXDATE" < '2013-2-2'
  OR "TXDATE" IS NULL;

See it in action:

• SQL Fiddle Demo