GBase 8s 常用系统函数
标量函数
数学函数
| 函数 | 说明 |
|---|---|
| abs | 返回绝对值 |
| ceil | 返回大于参数的数值 |
| floor | 返回小于参数的数值 |
| round | 返回参数的四舍五入数值 |
| mod | 返回第一个参数的模 |
| pow | 计算数值的N次方 |
| sqrt | 计算平方根 |
| root | 计算数值的N次方根 |
| exp | 计算指数 |
| ln | 计算自然对数 |
| logn | 计算自然对数 |
| log10 | 计算以10为底的对数 |
| sin | 计算正弦值 |
| cos | 计算余弦值 |
ABS
abs(num)
select abs(-5.6) as num1, abs(5.6) as num2 from dual;
> select abs(-5.6) as num1, abs(5.6) as num2 from dual;
num1 num2
5.60000000000000 5.60000000000000
1 row(s) retrieved.
>
CEIL/FLOOR/ ROUND
ceil(num)
floor(num)
round(num)
select ceil(5.6) as f_ceil, floor(5.6)as f_floor, round(5.6) as f_round from dual;
> select ceil(5.6) as f_ceil, floor(5.6)as f_floor, round(5.6) as f_round from dual;
f_ceil f_floor f_round
6 5 6
1 row(s) retrieved.
>
select ceil(5.3) as f_ceil, floor(5.3)as f_floor, round(5.3) as f_round from dual;
> select ceil(5.3) as f_ceil, floor(5.3)as f_floor, round(5.3) as f_round from dual;
f_ceil f_floor f_round
6 5 5
1 row(s) retrieved.
>
select ceil(-5.6) as f_ceil, floor(-5.6)as f_floor, round(-5.6) as f_round from dual;
> select ceil(-5.6) as f_ceil, floor(-5.6)as f_floor, round(-5.6) as f_round from dual;
f_ceil f_floor f_round
-5 -6 -6
1 row(s) retrieved.
>
select ceil(-5.3) as f_ceil, floor(-5.3)as f_floor, round(-5.3) as f_round from dual;
> select ceil(-5.3) as f_ceil, floor(-5.3)as f_floor, round(-5.3) as f_round from dual;
f_ceil f_floor f_round
-5 -6 -5
1 row(s) retrieved.
>
MOD
mod(num)
select mod(10, 3) as f_mod from dual;
> select mod(10, 3) as f_mod from dual;
f_mod
1
1 row(s) retrieved.
>
POW/SQRT/ROOT
pow(num1, num2)
sqrt(num)
root(num1, num2)
select pow(2, 3) as f_pow3, sqrt(25) as f_sqrt, root(64, 3) as f_root from dual;
> select pow(2, 3) as f_pow3, sqrt(25) as f_sqrt, root(64, 3) as f_root from dual;
f_pow3 f_sqrt f_root
8.000000000000 5.000000000000 4.000000000000
1 row(s) retrieved.
>
EXP
exp(num)
> select exp(1) as f_exp from dual;
f_exp
2.718281828459
1 row(s) retrieved.
>
LN/LOGN/LOG10
ln(num)
logn(num)
log10(num)
select ln(2.718281828459) as f_ln, logn(2.718281828459) as f_logn, log10(1000) as f_log10 from dual;
> select ln(2.718281828459) as f_ln, logn(2.718281828459) as f_logn, log10(1000) as f_log10 from dual;
f_ln f_logn f_log10
1.000000000000 1.000000000000 3.000000000000
1 row(s) retrieved.
>
SIN/COS
sin(num)
cos(num)
select sin(1) as f_sin, cos(1) as f_cos from dual;
> select sin(1) as f_sin, cos(1) as f_cos from dual;
f_sin f_cos
0.841470984808 0.540302305868
1 row(s) retrieved.
>
字符串函数
| 函数 | 说明 |
|---|---|
| CONCAT | 字符串拼接 |
| TRIM | 从字符串的开头或结尾移除指定字符 |
| LTRIM | 从字符串的开头移除指定字符 |
| RTRIM | 从字符串的结尾移除指定字符 |
| SUBSTR | 截取字符串 |
| SUBSTRB | 截取字符串 |
| SUBSTRING | 截取字符串 |
| INSTR | 返回字符串中指定子串的开始位置 |
| ASCII | 返回字符串第一个字符的编码 |
| REPLACE | 替换字符串中的部分内容 |
| UPPER | 将字符串的字母转成大写 |
| LOWER | 将字符串的字母转成小写 |
| LENGTH | 返回字符串的长度 |
| OCTET_LENGTH | 返回字符串的长度 |
| CHAR_LENGTH | 返回字符串的长度 |
| REGEXP_REPLACE | 使用正则表达式方式替换字符串中的内容 |
| REGEXP_SUBSTR | 使用正则表达式方式替换字符串中的内容 |
| REGEXT_INSTR | 计算字符串中指定正则表达式定义的字符串所在位置 |
CONCAT
concat(str1, str2)
select concat('Hello', 'World') as f_concat from dual;
> select concat('Hello', 'World') as f_concat from dual;
f_concat
HelloWorld
1 row(s) retrieved.
>
TRIM/LTRIM/RTRIMtrim(str)
trim(both ‘char’ from column_name)
ltrim(str)
ltrim(str, ‘char’)
rtrim(str)
rtrim(str, ‘char’)
select f_message,
octet_length(f_message) as f_len1,
octet_length(trim(f_message)) as f_len2,
octet_length(ltrim(f_message)) as f_len3,
octet_length(rtrim(f_message)) as f_len4
from (select ' Hello world ' as f_message from dual) t;
> select f_message,
octet_length(f_message) as f_len1,
octet_length(trim(f_message)) as f_len2,
octet_length(ltrim(f_message)) as f_len3,
octet_length(rtrim(f_message)) as f_len4
from (select ' Hello world ' as f_message from dual) t;
f_message f_len1 f_len2 f_len3 f_len4
Hello world 16 11 15 12
1 row(s) retrieved.
>
select f_message,
octet_length(f_message) as f_len1,
octet_length(trim(both '#' from f_message)) as f_len2,
octet_length(ltrim(f_message, '#')) as f_len3,
octet_length(rtrim(f_message, '#')) as f_len4
from
(select '#Hello world####' as f_message from dual) t;
> select f_message,
octet_length(f_message) as f_len1,
octet_length(trim(both '#' from f_message)) as f_len2,
octet_length(ltrim(f_message, '#')) as f_len3,
octet_length(rtrim(f_message, '#')) as f_len4
from
(select '#Hello world####' as f_message from dual) t;
f_message f_len1 f_len2 f_len3 f_len4
#Hello world#### 16 11 15 12
1 row(s) retrieved.
>
SUBSTR/SUBSTRB/SUBSTRING
substr(str, start, len)
substrb(str, start, len)
substring(str from start for len)
select substr('abcdefg', 2, 3) as f_substr from dual;
INSTR
instr(str1, str2, start, count)
select instr('How are you?', 'o', 1, 1) as f_instr1, instr('How are you?', 'o', 1, 2) as f_instr2 from dual;
> select instr('How are you?', 'o', 1, 1) as f_instr1, instr('How are you?', 'o', 1, 2) as f_instr2 from dual;
f_instr1 f_instr2
2 10
1 row(s) retrieved.
>
ASCII
ascii(str)
select ascii('Hello') as f_ascii1, ascii('world') as f_ascii2, ascii('冀辉') as f_ascii3 from dual;
select ascii('冀') as f_ascii1, ascii('辉') as f_ascii2, ascii('冀辉') as f_ascii3 from dual;
> select ascii('Hello') as f_ascii1, ascii('world') as f_ascii2, ascii('冀辉