oracle sql时间比较

Question

I have this oracle table and the following data:

CREATE TABLE data( 
 fielda DATE DEFAULT sysdate, //sample data: 06/02/2021
  fieldb TIMESTAMP(6) WITH LOCAL TIME ZONE DEFAULT current_timestamp //sample data:05/02/2021 11:44:04.000000000
);

I want to list all records in table data, where timea is not equal to timeb.

I wrote this query:

select * from  data where TO_DATE(timea, 'dd/mm/yyyy') != TO_DATE(timea, 'dd/MM/yyyy hh24:mi:ss') ;

but i get error: ORA-01830: date format picture ends before converting entire input string

Do advise how to list all records in table a, where timea is not equal to timeb.

Answer 1

oracle basic data types: date and timestamp are two different data types. the last one is more percise. your to_date conversion seems very wired. to_date convert a string (text format) to a date. according your table defination, fielda is a date type. why do the convert? what is the parameter timea? to_date(timea,...),= to_date(timea...?) whats your point, supporsed you are try to query some record which not match the specified date. the where clause should be like " where sometable,somefiled != to_date('specified_date_string_with_format','specified_format')"