不使用function计算给定两个日期之间的工作日个数

核心提示：可能这就是Oracle的work_days函数的算法吧Calculating Working Days Without Using a Function This tip comes from Mike Selvaggio, Senior DB Architect and DBA at Orsel Consulting

　　可能这就是Oracle的work_days函数的算法吧
　　
　　Calculating Working Days Without Using a Function
　　
　　This tip comes from Mike Selvaggio, Senior DB Architect and DBA at Orsel Consulting Inc. in North Brunswick, NJ.
　　
　　If you need to calculate working days between two dates and you can't create the Oracle-recommended working days function, here is SQL that can accomplish the same task:
　　
　　SQL> set linesize 100
　　SQL> desc date_test
　　Name Null? Type
　　START_DT DATE
　　END_DT DATE
　　
　　SQL> select * from date_test
　　2 .
　　SQL> /
　　
　　START_DT END_DT
　　--------- ---------
　　13-DEC-02 18-DEC-02
　　17-DEC-02 19-DEC-02
　　18-DEC-02 23-DEC-02
　　26-DEC-02 28-DEC-02
　　
　　SQL> select start_dt, end_dt, end_dt - start_dt age,
　　work_days(start_dt, end_dt) from date_test;
　　
　　START_DT END_DT AGE WORK_DAYS(START_DT,END_DT)
　　--------- --------- ---------- --------------------------
　　13-DEC-02 18-DEC-02 5 3
　　17-DEC-02 19-DEC-02 2 2
　　18-DEC-02 23-DEC-02 5 3
　　26-DEC-02 28-DEC-02 2 1
　　
　　
　　SQL> get workingdays
　　代码：
　　select　start_dt, end_dt, trunc(end_dt - start_dt) age,
　　(trunc(end_dt - start_dt) - (
　　(case
　　WHEN (8-to_number(to_char(start_dt,'D') )) > trunc(end_dt -start_dt)+1
　　THEN 0
　　ELSE
　　trunc( (trunc(end_dt - start_dt) -(8-to_number(to_char(start_dt,'D') ))) / 7 ) + 1 END) +
　　(case
　　WHEN mod(8-to_char(start_dt,'D'),7) > trunc(end_dt - start_dt)-1
　　THEN 0
　　ELSE
　　trunc( (trunc(end_dt-start_dt) - (mod(8-to_char(start_dt,'D'),7)+1)) / 7 ) + 1
　　　END) ) ) workingdays
　　from date_test
　　
　　SQL> /
　　
　　START_DT END_DT AGE WORKINGDAYS
　　--------- --------- ---------- -----------
　　13-DEC-02 18-DEC-02 5 3
　　17-DEC-02 19-DEC-02 2 2
　　18-DEC-02 23-DEC-02 5 3
　　26-DEC-02 28-DEC-02 2 1