万恶之源-SQL

ORACLE的SQL输出下个月第一个周日的日期

 

SYS@ prod>SELECT TO_CHAR(NEXT_DAY(LAST_DAY(SYSDATE), 'SUN'),'dd "is the first Sunday for" fmmonth rrrr') "第一个周日的日期" FROM DUAL;
SELECT TO_CHAR(NEXT_DAY(LAST_DAY(SYSDATE), 'SUN'),'dd "is the first Sunday for" fmmonth rrrr') "第一个周日的日期" FROM DUAL
                                           *
第 1 行出现错误:
ORA-01846: 周中的日无效


SYS@ prod>alter session  set nls_date_language='american';

会话已更改。

SYS@ prod>SELECT TO_CHAR(NEXT_DAY(LAST_DAY(SYSDATE), 'SUN'),'dd "is the first Sunday for" fmmonth rrrr') "第一个周日的日期" FROM DUAL;

第一个周日的日期
---------------------------------------------------------------------------------------------------------------------------------------
04 is the first Sunday for april 2021

You want to display the date for the first Monday of the next month and issue the following command:

SQL>SELECT TO_CHAR(NEXT_DAY(LAST_DAY(SYSDATE), 'MON'),

'dd "is the first Monday for" fmmonth rrrr')

FROM DUAL;

What is the outcome?

A.In generates an error because rrrr should be replaced by rr

in the format string.

B.It executes successfully but does not return the correct result.

C.It executes successfully and returns the correct result.

D.In generates an error because TO_CHAR should be replaced with TO_DATE .

E.In generates an error because fm and double quotation marks should not be used in the format string.

Answer: C

 

 

 

Jrojyun

2021-03-24