MySQL database functions

One: String function:

1.concat ();

Concat (S1,s2,s3,...... SN);

Link the incoming parameters into a string;

2.insert ();

Insert (Str,x,y,insert);

St R: The passed-in string,

X: Starting from the first few

Y: You need to replace several characters

Insert: String to replace

　　

3.lower (), Upper ()

Lower (): string converted to uppercase;

Upper (): string converted to lowercase;

　　　

4.left (str,x) Right (Str,y)

STR: The string to be returned

X: Returns the number of characters

5.rpad (Str,n,pad)

STR: Characters that need to be populated

N: Length of the string after padding

Pad: Characters that need to be populated

6.trime ()

Remove spaces on both sides of the string

7.replace (STR,A,B)

STR: The string to be replaced

Use string B to replace a in Str

8.STRCMP (S1,S2)

Returns 1 if S1 is greater than S2

If S1 is less than S2 returns-1

If S1 equals S2 returns 0

9.substring (Str,x,y)

STR: The string to be returned

X: Starting at position x

Y: Take y characters

Two: Numerical functions:

1.ABS (x) returns the absolute value of X

2.ceil (x) returns the minimum value greater than X

3.floor (x) returns the maximum value less than X

4.med (x, y) returns the Touch (redundancy) of X, Y

5.rand () return random number

6.round (x, y) returns the value of the rounding Y position of X (rounded)

7.truncate (x, y) returns the fractional result of a number x truncated to Y;

Three: Time function:

1.curdate () returns the current date 2014-7-4

2.curtime () returns the current time 12:00:01

3.now () returns the current time 2014-7-4 12:00:01

4.unix-time (now ()) returns the current timestamp 1293433835

5.time () timestamp conversion time (1293433835)

6.week () returns the current day of the week

7.data_format () Format current time Date_format (now (), '%b%d%Y%h:%i%p ') Dec 11:45 PM