Shulou(Shulou.com)06/01 Report--

One-line function: only one parameter input, only one result output

Multiline function or grouping function: can have multiple parameter inputs and only one result output

Test the lower/upper/initcap function, using the dual dumb table

Select lower ('www.BAIdu.COM') from dual;select upper (' www.BAIdu.COM') from dual;select initcap ('www.BAIdu.COM') from dual

Test the concat/substr function, starting with 1, to represent characters, both Chinese and English

Select concat ('hello',' Hello') from dual; is correct

Select concat ('hello',' Hello', 'World') from dual; error

Select 'hello' | |' Hello'| | 'World' from dual; is correct

Select concat ('hello',concat (' Hello', 'World') from dual; is correct

Select substr ('hello Hello', 5jol 3) from dual

5 means that it starts with the first character, and the first character is 1, which is processed in both Chinese and English.

3 means to take several characters in succession

Test the length/lengthb function. The encoding method is UTF8/GBK. One Chinese account for 2 bytes and one English one byte.

Select length ('hello Hello') from dual; select lengthb ('hello Hello') from dual

Test the instr/lpad/rpad function to find the first occurrence from left to right, starting with 1

Select instr ('helloworld','o') from dual

Note: no return is found, case sensitive

Select LPAD ('hello',10,'#') from dual;select RPAD (' hello',10,'#') from dual

Test trim/replace function

Select trim ('from' hell') from dual;select replace ('hello','l','L') from dual

Test the round/trunc/mod function on the numerical type

Select round (3.1415) from dual;select trunc (3.1415) from dual;select mod (10) from dual

Current date:

Select sysdate from dual

Test the effect of round on date (month)

Select round (sysdate,'month') from dual

Test the effect of round on date (year)

Select round (sysdate,'year') from dual

Test the effect of trunc on date (month)

Select trunc (sysdate,'month') from dual

Test the effect of trunc on date (year)

Select trunc (sysdate,'year') from dual

Show yesterday, today, tomorrow's date, date type +-value = date type

Select sysdate-1 "yesterday", sysdate "Today", sysdate+1 "tomorrow" from dual

The approximate length of service of the employee is displayed in the form of year and month, date-date = value, assuming: 365 days in a year and 30 days in January

Select ename "name", round (sysdate-hiredate,0) / 365seniority from emp

Use the months_between function to calculate exactly how many months there are until the end of the year

Select months_between ('31-December-16 September September Sysdate) from dual

Use the months_between function to display the length of service of employees in the form of precise months

Select ename "name", months_between (sysdate,hiredate) "precise monthly length of service" from emp

Test the add_months function, what's the date today next month?

Select add_months (sysdate,1) from dual

Test the add_months function, what's the date today last month?

Select add_months (sysdate,-1) from dual

Test the next_day function, starting from today, what's the date next Wednesday [Chinese platform]

Select next_day (sysdate,' Wednesday') from dual

Test the next_day function, starting from today, what is the number of the following Wednesday [Chinese platform]

Select next_day (next_day (sysdate,' Wednesday'), 'Wednesday') from dual

Test the next_day function, starting from today, what is the date of the next Wednesday and the next Sunday [Chinese platform]

Select next_day (next_day (sysdate,' Wednesday'), 'Sunday') from dual

Test the last_day function, what is the last day of this month?

Select last_day (sysdate) from dual

Test the last_day function, what is the number on the penultimate day of this month

Select last_day (sysdate)-1 from dual

Test the last_day function, what is the last day of the next month?

Select last_day (add_months (sysdate,1)) from dual

Test the last_day function, what is the last day of the last month?

Select last_day (add_months (sysdate,-1)) from dual

Note:

1) date-date = number of days

2) date +-days = date

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