Oracle PL/SQL split csv string into n parts - oracle

Question

I need to split a csv string into n parts. I have addresses in various formats, so I converted them to a csv string. My report requires 3 or 4 address line fields, so I want to split my csv string into the number of parts the report requires.
For example:
10,Dingle Apartments,MANZINI,,MANZINI,NGWANE STREET,,,Swaziland
should be split into equal parts for 3 fields:
1:10,Dingle Apartments,MANZINI
2:,MANZINI,NGWANE STREET
3:,,,Swaziland
I wrote the following code, but it does not work well at all:
-- ============================================================================
-- This function splits a csv string into x parts and returns one of the parts.
-- Note: The smallest number of items in a part is hard coded to 2. Needs debug.
--
-- p_string - The csv string.
-- p_parts - The number of parts to split into.
-- p_part - The splitted part to return.
-- p_separator - The separator used in the csv string.
-- p_separator_out - The separator to return.
-- p_trim - Trim trailing separator. Y/N
-- ============================================================================
function get_csv_part
(
p_string in varchar2,
p_parts in number,
p_part in number,
p_separator in varchar2,
p_separator_out in varchar2,
p_trim in varchar2 default 'Y'
) return varchar2 is
l_answer varchar2(32767) := '';
l_count number := 0;
l_count2 number := 0;
l_size number;
l_pos number;
l_pos2 number;
begin
-- hr_utility.trace_on(null, 'FDL');
hr_utility.trace('p_string: ' || p_string);
l_pos := instr(p_string, p_separator);
-- Determine the number of separators.
while l_pos > 0 loop
l_count := l_count + 1;
l_pos := instr(p_string, p_separator, l_pos + 1);
end loop;
-- Get the size of a part.
if l_count <= p_parts then
l_size := 2;
else
l_size := floor(l_count / p_parts);
end if;
--if l_size = 1 then
-- l_size := 2;
--end if;
hr_utility.trace('l_size: ' || to_char(l_size));
l_pos := instr(p_string, p_separator);
if l_pos = 0 then
if p_part = 1 then
l_answer := p_string;
end if;
else
if p_part = 1 then
l_answer := substr(p_string, 1, l_pos - 1) || p_separator_out;
end if;
end if;
-- Split csv into parts.
while l_pos > 0 loop
l_count2 := l_count2 + 1;
l_pos2 := instr(p_string, p_separator, l_pos + 1);
hr_utility.trace('----------------------------------------');
hr_utility.trace('l_count: ' || to_char(l_count));
hr_utility.trace('l_count2: ' || to_char(l_count2));
hr_utility.trace('floor(l_count2 / l_size) + 1: ' || to_char(floor(l_count2 / l_size) + 1));
hr_utility.trace('l_pos: ' || to_char(l_pos));
hr_utility.trace('l_pos2: ' || to_char(l_pos2));
hr_utility.trace('l_answer: ' || l_answer);
-- If we are at a position that should go into the returned part.
if
(
l_size > 1
and floor(l_count2 / l_size) + 1 = p_part
)
or
(
l_size = 1
and l_count2 = p_part
)
or
(
p_part = p_parts
and l_size = 1
and l_count2 >= p_part
)
or
(
p_part = p_parts
and floor(l_count2 / l_size) + 1 >= p_part
) then
if l_pos2 = 0 then
if l_pos + 1 < length(p_string) then
l_answer := l_answer || substr(p_string, l_pos + 1) || p_separator_out;
end if;
elsif ((l_pos + 1) <= (l_pos2 - 1)) then
l_answer := l_answer || substr(p_string, l_pos + 1, ((l_pos2 - 1) - (l_pos + 1) + 1)) || p_separator_out;
else
l_answer := l_answer || p_separator_out;
end if;
end if;
l_pos := l_pos2;
end loop;
if p_part = p_parts then
l_pos := instr(p_string, p_separator, 1, l_count);
-- Dodge.
if instr(p_string, substr(p_string, l_pos + 1)) = 0 then
l_answer := l_answer || substr(p_string, l_pos + 1);
end if;
end if;
if p_trim = 'Y' then
-- Did not work if all separators.
-- l_answer := trim(trailing p_separator_out from l_answer);
if substr(l_answer, length(l_answer)) = p_separator_out then
l_answer := substr(l_answer, 1, length(l_answer) - 1);
end if;
end if;
return l_answer;
end get_csv_part;
Some of the issues are:
It does not work for part size of 1
It puts address parts into multiple parts, for example ,,TEST,SWAZILIND,LOCATION,THING,,,,
It skips address parts
It uses unequal part sizes.
Note that for some reason the requirement is to leave the blank fields with separators so a part could be ,
Can anyone help me fix this or does anyone have a function that can do this?

Answer 1

Untested but something like:
CREATE OR REPLACE function get_csv_part(
p_string in varchar2,
p_parts in number,
p_part in number,
p_separator in varchar2,
p_separator_out in varchar2,
p_trim in varchar2 default 'Y'
)
RETURN VARCHAR2 DETERMINISTIC
IS
p_value VARCHAR2(4000) := p_string;
p_start INTEGER;
p_end INTEGER;
p_items INTEGER;
p_sep_len CONSTANT INTEGER := LENGTH( p_separator );
BEGIN
IF p_value IS NULL THEN
RETURN NULL;
END IF;
p_items = ( LENGTH( p_value ) - LENGTH( REPLACE( p_value, p_separator ) ) ) / p_sep_len + 1;
IF p_part = 1 THEN
p_start := 1;
ELSE
p_start := INSTR( p_value, p_separator, 1, ROUND( ( p_part - 1 ) / p_parts * p_items ) ) + p_sep_len;
END IF;
p_end := INSTR( p_value, p_separator, 1, ROUND( p_part / p_parts * p_items ) ) - 1;
IF p_end = -1 THEN
p_value := SUBSTR( p_value, p_start );
ELSE
p_value := SUBSTR( p_value, p_start, p_end - p_start + 1 );
END IF;
IF p_trim = 'Y' THEN
WHILE SUBSTR( p_value, -p_sep_len ) = p_separator THEN
p_value := SUBSTR( p_value, 1, LENGTH( p_value ) - p_sep_len );
END LOOP;
END IF;
RETURN REPLACE( p_value, p_separator, p_separator_out );
END;
/