MySQL Learning--commonly used functions (String functions)

String functions in MySQL

Function	Function
CONCAT (s1,s2,... sn)	Connect S1,s1...sn to a string
INSERT (STR,X,Y,INSTR)	The string str starts at the x position, and the substring of y characters is replaced with the string instr
LOWER (str)	Turns the string str into lowercase
UPPER (str)	Turn string str to uppercase
Left (str,x)	Returns the character of the leftmost x of the string str
Right (STR,X)	Returns the character of the rightmost x of a string
Lpad (Str,n,pad)	Fill the leftmost str with a string pad until the length is N string length
Rpad (Str,n,pad)	Padding the rightmost of str with a string pad until the length is N string length
LTRIM (str)	Remove string Str left space
RTRIM (str)	Remove string str right space
REPEAT (str,x)	Returns the result of repeated x times of STR
REPLACE (STR,A,B)	Substitute string B for string A in str
STRCMP (S1,S2)	Compare String S1,s2
TRIM (str)	Remove string line endings and wardrobe spaces
SUBSTRING (Str,x,y)	Returns a string of Y-length strings from the str x position of the string

CONCAT: Concatenate incoming arguments into a string, any string and null join IS NULL

　　　　

INSERT: The string str starts at position x, and the substring of y characters is replaced with a string instr

　　　　

Lower,upper: Converts a string to lowercase or uppercase

　　　　

Left,right: Returns the leftmost and rightmost x characters of the string, if the second argument is null, there will be no return

　　　

Lpad,rpad: Padding with the leftmost and rightmost characters of the string str until the length is n strings

　　

Ltirm,rtirm: Remove string str left and right spaces

　　

REPEAT: Returns the result of repeated x times of STR

　　

Replace: Substitute string B for string A in str

　　

STRCMP: The size of the ASCLL code of the string S1 and S2, if S1 is smaller than S2 return -1,s1 and S2 equals return 0,s1 greater than S2 return 1

　　

TRIM: Removes whitespace at the beginning and end of the target string

　　

SUBSTRING: Returns a string of y string lengths from position x in str

　　

MySQL Learning--commonly used functions (String functions)