| 21. 10. 2. TRUNC and ROUND |
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TRUNC (value,'W') is the easiest way of getting the first day of the week. |
TRUNC, typically applied to numbers, also work with dates and timestamps. |
TRUNC truncates the date to some level of precision. |
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v_dt:= TRUNC (DATE|TIMESTAMP|INTERVAL value[,PRECISION]);
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Rather than numeric precision, here you use date format masks. |
For example, 'YYYY' truncates the date to years, and 'MM' to a month. |
If you don't specify any precision, the default is day ('DD'). |
You can't specify a combination of format masks. |
Only one can be specified at a time. |
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SQL>
SQL>
SQL> declare
2 v_dt DATE;
3 v_form_tx VARCHAR2(25):='YYYY-MM-DD HH24:MI:SS';
4 begin
5 v_dt:=trunc(sysdate);
6 DBMS_OUTPUT.put_line(to_char(v_dt,v_form_tx));
7 v_dt:=trunc(sysdate,'YYYY');
8 DBMS_OUTPUT.put_line(to_char(v_dt,v_form_tx));
9 end;
10 /
2007-06-09 00:00:00
2007-01-01 00:00:00
PL/SQL procedure successfully completed.
SQL>
SQL>
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