An introduction to Oracle Database-- one-line function

1, one-line function

SQL >-- character function

SQL > select lower ('Hello World') turns to lowercase, upper (' Hello World') turns to uppercase, initcap ('hello world') initials uppercase

2 from dual

Turn lowercase to uppercase

Hello world HELLO WORLD Hello World

SQL >-- substr (aforme b) start with bit b in a

SQL > select substr ('Hello World',4) substring from dual

Substring

Lo World

SQL >-- substr (aheline bjorc) start with bit b in an and take bit c

SQL > select substr ('Hello World',4,3) substring from dual

Son

Lo

SQL >-- number of length characters and lengthb bytes

SQL > select length ('Hello World') character, lengthb (' Hello World') byte from dual

Character byte 11 11

SQL > ed

Written to file afiedt.buf

1 * select length ('Beijing') character, lengthb ('Beijing') byte from dual

SQL > /

Character byte 2 4

SQL >-- instr (aforme b)

SQL >-- in a, look for b

SQL > select instr ('Hello World','ll') location from dual

Location 3

SQL >-- lpad left fill rpad right fill

SQL >-- abcd-> 10 bits

SQL > select lpad ('abcd',10,'') left, rpad (' abcd',10,'') right from dual

Left and right

* * abcd abcd**

SQL >-- trim removes the specified characters before and after

SQL > select trim ('H' from 'Hello WorldH') from dual

TRIM ('H'FR

Ello World

SQL >-- replace

SQL > select replace ('Hello World','l','*') from dual

REPLACE ('HE

He*o Word

SQL > host cls

SQL >-- rounding

SQL > select round (45.926) one, round (45.926) two, round (45.926) three, round (45.926)) four, round (45.926)

2 from dual

One, two, three, four, five, 45.93, 45.9, 46, 500.

SQL >-truncation

SQL > ed