MySQL function

– ================ Built in functions ================
– Numerical function
abs(x) – The absolute value abs(-10.9) = 10
format(x, d) – Format the number of thousandths format(1234567.456, 2) = 1,234,567.46
ceil(x) – Rounding up ceil(10.1) = 11
floor(x) – Rounding down floor (10.1) = 10
round(x) – Round to the nearest whole
mod(m, n) – m%n m mod n Seeking remainder 10%3=1
pi() – Get the pi
pow(m, n) – m^n
sqrt(x) – Arithmetical square root
rand() – random number
truncate(x, d) – Intercept d Decimal place

– Time date function
now(), current_timestamp(); – Current date time
current_date(); – The current date
current_time(); – current time
date(‘yyyy-mm-dd hh:ii:ss’); – Get the date part
time(‘yyyy-mm-dd hh:ii:ss’); – Get the time part
date_format(‘yyyy-mm-dd hh:ii:ss’, ‘%d %y %a %d %m %b %j’); – Format time
unix_timestamp(); – get unix Time stamp
from_unixtime(); – Get the time from the time stamp

– String function
length(string) – string length , byte
char_length(string) – string Characters of
substring(str, position [,length]) – from str Of position Start , take length Characters
replace(str ,search_str ,replace_str) – stay str of use replace_str Replace search_str
instr(string ,substring) – return substring First time in string Where in
concat(string [,…]) – Connection string
charset(str) – Returns the string character set
lcase(string) – Convert to lowercase
left(string, length) – from string2 From the left side of length Characters
load_file(file_name) – Read from file
locate(substring, string [,start_position]) – Same as instr, But you can specify the starting position
lpad(string, length, pad) – Repeat pad Add to string start , Until the string length is length
ltrim(string) – Remove the front space
repeat(string, count) – repeat count Time
rpad(string, length, pad) -- stay str After use pad Add , Until the length is length
rtrim(string) – Remove back-end space
strcmp(string1 ,string2) – Compare the size of two strings character by character

– Aggregate functions
count()
sum();
max();
min();
avg();
group_concat()

– Other common functions
md5();
default();