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Create Strip, LStrip, RStrip Functions in Redshift

There is no redshift inbuilt function to strip a character from start-end of a string.

For eg. if a numeric value is stored as a character with preceding zeros ' 0000123' and you want to store/operate/aggregate/join it as a number it is not possible with inbuilt redshift functions.  What you can do is to create the following strip udfs and make a use of these.

 lstrip : strips out the left instances of a character from a string.

CREATE OR REPLACE FUNCTION public.fn_lstrip(str_in character varying, a character)
RETURNS character varying AS
' try:
return(str_in.lstrip(a))
except:
return None'
LANGUAGE plpythonu VOLATILE;

eg. select public.fn_lstrip('00001234','0') would result in 12345

 rstrip : strips out the right instances of a character from a string.

 CREATE OR REPLACE FUNCTION public.fn_rstrip(str_in character varying, a character)
RETURNS character varying AS
' try:
return(str_in.rstrip(a))
except:
return None'
LANGUAGE plpythonu VOLATILE;


eg. select public.fn_lstrip('12340000','0') would result in 12345

 strip:  strips out the left & right instances of a character from a string.

 CREATE OR REPLACE FUNCTION public.fn_strip(str_in character varying, a character)
RETURNS character varying AS
' try:
return(str_in.strip(a))
except:
return None'
LANGUAGE plpythonu VOLATILE;


eg. select public.fn_lstrip('000012340000','0') would result in 12345
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