日期对指定的月份无效

Question

运行此Oracle SQL语句时出现问题:

SELECT * 
  FROM tbl_content
 WHERE last_updated >= (systimestamp - INTERVAL '1' month(1)) 
 ORDER BY last_updated desc  

而这个错误:

    java.sql.SQLException: ORA-01839: date not valid for month specified

    at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:111)
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:330)
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:287)
    at oracle.jdbc.driver.T4C8Oall.receive(T4C8Oall.java:742)
    at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:212)
    at oracle.jdbc.driver.T4CPreparedStatement.executeForRows(T4CPreparedStatement.java:951)
    at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1053)
    at oracle.jdbc.driver.T4CPreparedStatement.executeMaybeDescribe(T4CPreparedStatement.java:835)
    at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1123)
    at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3284)
    at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3328)
    at com.vtdd.sms.content.xskt.XsktService.getKQXSFollowArea(XsktService.java:4044)
    at com.vtdd.sms.content.xskt.XsktService.getMessages(XsktService.java:421)
    at com.vht.sms.content.ContentAbstract.getSubmitMessages(ContentAbstract.java:47)
    at com.vht.sms.content.ContentFactory.getSubmitMessages(ContentFactory.java:335)
    at com.vht.sms.content.ContentFactory.run(ContentFactory.java:62)
    at java.lang.Thread.run(Thread.java:662)  

你能告诉我有什么问题吗？

Answer 1

首先,你为什么用systimestamp？如果你想要这个月,那肯定sysdate是足够的吗？其次,我喜欢 - 也就是个人喜好 - 非常清楚发生了什么.Oracle有一个add_months功能,它可以做你想要的.所以你的查询很容易:

SELECT * 
  FROM tbl_content
 WHERE last_updated >= add_months(sysdate, -1) 
 ORDER BY last_updated desc