如何取时间字段比当前时间早的语句

Question

select * from tbname where trunc(dtcol,'dd')<trunc(add_months(sysdate,-3),'dd');

Answer 1

10:58:51 jlanzpa817>select add_months(sysdate,-3) from dual;ADD_MONTHS(SYSDATE,
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2002.09.20 11:06:13已用时间:  00: 00: 00.10

Answer 2

select * from tbname where trunc(dtcol)<trunc(add_months(sysdate,-3));

Answer 3

select * from table where trunc(col_date,'mm')<trunc(add_months(sysdate,-3),'mm');也可以
select * from table where to_char(col_date,'yyyymm')<to_char(add_months(sysdate,-3),'yyyymm');