OpenEdge Data Management:<br />SQL Reference PREFIX

Returns the substring of a character string, starting from the position specified by start_pos and ending before the specified character.

Syntax

PREFIX ( char_expression , start_pos , char_expression )

Evaluates to a character string, typically a character-string literal or column name. If the expression evaluates to NULL, PREFIX returns NULL.

Evaluates to an integer value. PREFIX searches the string specified in the first argument starting at that position. A value of 1 indicates the first character of the string.

Evaluates to a single character. PREFIX returns the substring that ends before that character. If PREFIX does not find the character, it returns the substring beginning at start_pos, to the end of the string. If the expression evaluates to more than one character, PREFIX ignores all but the first character.

create table prefix_table ( colstring varchar(20), colchar char(1) ); insert into prefix_table values ('string.with.dots', '.'); insert into prefix_table values ('string-with-dashes', '-'); select colstring, colchar, prefix(colstring, 1, '.') from prefix_table; COLSTRING COLCHAR prefix(COLSTRING,1,.) --------------------- --------------------- ---------------------- string.with.dots . string string-with-dashes - string-with-dashes select colstring, colchar, prefix(colstring, 1, colchar) from prefix_table; COLSTRING COLCHAR prefix(COLSTRING,1,COLCHAR) --------------------- --------------------- ---------------------------- string.with.dots . string string-with-dashes - string select colstring, colchar, prefix(colstring, 1, 'X') from prefix_table; COLSTRING COLCHAR prefix(COLSTRING,1,X) --------------------- --------------------- ---------------------- string.with.dots . string.with.dots string-with-dashes - string-with-dashes

create table prefix_table  
     ( 
     colstring varchar(20), 
     colchar char(1) 
     ); 
  
insert into prefix_table values ('string.with.dots', '.'); 
  
insert into prefix_table values ('string-with-dashes', '-'); 
  
select colstring, colchar, prefix(colstring, 1, '.') from prefix_table; 
COLSTRING             COLCHAR               prefix(COLSTRING,1,.)   
--------------------- --------------------- ----------------------  
string.with.dots      .                     string                  
string-with-dashes    -                     string-with-dashes      
  
  
select colstring, colchar, prefix(colstring, 1, colchar) from prefix_table; 
  
COLSTRING             COLCHAR               prefix(COLSTRING,1,COLCHAR)   
--------------------- --------------------- ----------------------------  
string.with.dots      .                     string                        
string-with-dashes    -                     string                        
  
  
select colstring, colchar, prefix(colstring, 1, 'X') from prefix_table; 
  
COLSTRING             COLCHAR               prefix(COLSTRING,1,X)   
--------------------- --------------------- ----------------------  
string.with.dots      .                     string.with.dots        
string-with-dashes    -                     string-with-dashes

Note

Each char_expression and the result can contain multi-byte characters. The start_pos argument specifies the character position, not a byte position. Character comparisons are case sensitive and are determined by sort weights in the collation table in the database.

PREFIX

Syntax

Note

Compatibility