[ http://issues.apache.org/jira/browse/DERBY-896?page=comments#action_12364754 ]
Oleksandr Alesinskyy commented on DERBY-896: -------------------------------------------- Casting from TIMESTAMP to DATE (as well as to TIME) is supported by Derby by means of normal CAST function, so built-in DATE(TIMESTAMP) and TIME(TIMESTAMP) are superflous (but probably have to be maintained for backward compatibility). e.g. CAST(current_timestamp as date) works CAST(current_date as timestamp) does NOT work > Cast date to timestamp results in "ERROR 42846: Cannot convert types 'DATE' > to 'TIMESTAMP'." > -------------------------------------------------------------------------------------------- > > Key: DERBY-896 > URL: http://issues.apache.org/jira/browse/DERBY-896 > Project: Derby > Type: Bug > Versions: 10.1.2.1 > Environment: --------- Derby Information -------- > JRE - JDBC: J2SE 1.4.2 - JDBC 3.0 > [D:\Programme\Derby\bin\lib\derby.jar] 10.1.2.1 - (330608) > [D:\Programme\Derby\bin\lib\derbytools.jar] 10.1.2.1 - (330608) > Reporter: Oleksandr Alesinskyy > > Cast date to timestamp results in "ERROR 42846: Cannot convert types 'DATE' > to 'TIMESTAMP'.", > e.g. in ij: > select cast(cast ('2006-01-01' as date) as timestamp) from sys.sysschemas; > or > select cast (current_date as timestamp) from bradi_dat.lpaip01; > The similar issue exists for time ("ERROR 42846: Cannot convert types 'TIME' > to 'TIMESTAMP'.", > Documentation clearly states that these conversions are allowed, see table 1 > in a description of CAST function in the Derby Reference Manual and comment > about "Conversion of date/time values" below that table (see below as well). > Conversions of date/time values > A date/time value can always be converted to and from a TIMESTAMP. If a DATE > is > converted to a TIMESTAMP, the TIME component of the resulting TIMESTAMP is > always > 00:00:00. If a TIME data value is converted to a TIMESTAMP, the DATE > component is > set to the value of CURRENT_DATE at the time the CAST is executed. If a > TIMESTAMP > is converted to a DATE, the TIME component is silently truncated. If a > TIMESTAMP is > converted to a TIME, the DATE component is silently truncated. > -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
