stringfunc.hlp

关系型数据库 Postgresql 6.5.2

.pgaw:Help.f.t insert end \
"String functions\n\n" {title} \
"SQL92 String Functions" {bold} \
" - SQL92 defines string functions with specific syntax. Some of these are implemented using other Postgres functions. The supported string types for SQL92 are char, varchar, and text. 
" {} "
char_length(string)" {bold} " 
	Returns: int4 
	length of string" {} "

character_length(string)" {bold} " 
	Returns: int4 
	length of string" {} " 

lower(string)" {bold} " 
	Returns: string 
	convert string to lower case" {} " 

octet_length(string)" {bold} " 
	Returns: int4 
	storage length of string" {} " 

position(string in string)" {bold} " 
	Returns: int4 
	location of specified substring" {} " 

substring(string \[from int\] \[for int\])" {bold} " 
	Returns: string 
	extract specified substring" {} " 

trim(\[leading|trailing|both\] \[string\] from string)" {bold} " 
	Returns: string 
	trim characters from string" {} " 

upper(text)" {bold} " 
	Returns: text 
	convert text to upper case 

Many additional string functions are available for text, varchar(), and char() types. Some are used internally to implement the SQL92 string functions listed above. 

" {} "PostgreSQL String Functions

char(text)" {bold} " 
	Returns: char 
	convert text to char type 

" {} "char(varchar)" {bold} " 
	Returns: char 
	convert varchar to char type 

" {} "initcap(text)" {bold} " 
	Returns: text 
	first letter of each word to upper case 

" {} "lpad(text,int,text)" {bold} " 
	Returns: text 
	left pad string to specified length 

" {} "ltrim(text,text)" {bold} " 
	Returns: text 
	left trim characters from text 

" {} "textpos(text,text)" {bold} " 
	Returns:text 
	locate specified substring 

" {} "rpad(text,int,text)" {bold} "
	Returns: text
	right pad string to specified length 

" {} "rtrim(text,text)" {bold} " 
	Returns: text 
	right trim characters from text 

" {} "substr(text,int\[,int\])" {bold} " 
	Returns: text 
	extract specified substring 

" {} "text(char)" {bold} " 
	Returns: text 
	convert char to text type 

" {} "text(varchar)" {bold} " 
	Returns: text 
	convert varchar to text type 

" {} "translate(text,from,to)" {bold} " 
	Returns: text 
	convert character in string 

" {} "varchar(char)" {bold} " 
	Returns: varchar 
	convert char to varchar type 

" {} "varchar(text)" {bold} " 
	Returns: varchar 
	convert text to varchar type 

Most functions explicitly defined for text will work for char() and varchar() arguments. 

" {} \
"PostgreSQL functions\n" {link pgfunctions} \
"Next - Date/Time functions" {link datefunc}