derby 数据库中 TIMESTAMPDIFF函数怎么用？

Question

derby 数据库中 TIMESTAMPDIFF( interval, timestampExpression1, timestampExpression2 )函数怎么用？

Answer 1

谢谢

Answer 2

timestampdiff(week,’2009-01-24′,’2009-06-20′) 

imestampdiff(day,’2009-01-24′,’2009-06-20′)

Answer 3

TIMESTAMPDIFF is a JDBC escaped function, and is only accessible using the JDBC escape function syntax. The syntax you need is:

select {fn timestampdiff(SQL_TSI_WEEK, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)} from demo.field;

TIMESTAMPDIFF( interval, timestampExpression1, timestampExpression2 )  

三个参数，第二和第三个参数是timestamp类型的时间函数，第一个参数是（timestampExpression2-timestampExpression1）的时间差的表示单位，如SQL_TSI_SECOND是以秒为单位，返回两个查询参数的时间差。
    1）interval的类型还有：SQL_TSI_DAY 、SQL_TSI_FRAC_SECOND、SQL_TSI_HOUR、SQL_TSI_MINUTE、SQL_TSI_MONTH、 SQL_TSI_QUARTER、SQL_TSI_SECOND、SQL_TSI_WEEK、SQL_TSI_YEAR