How do I get the ASCII value of a string as an int in PostgreSQL?
For example: the string S06.6X9A
Currently, I am using an ASCII function, but it returns only the first character of a given string.
Use string_to_array('S06.6X9A', null) to split the string into a text[] of individual characters. Then unnest to turn that text[] into a table. Then use that in a from clause and run ascii() over each row.
select ascii(char)
from (
select unnest( string_to_array('S06.6X9A', null) )
) as chars(char);
ascii
-------
83
48
54
46
54
88
57
65
Simpler than Schwern's answer is:
SELECT ascii( unnest( string_to_array('S06.6X9A', NULL) ) )
Related
In Postgresql, I need to take an ASCII string like CNR39XL and turn it into a number like 21317392311 (ASCII values - 65, but digits left as is). This is to take some logic in our software and push it down into the databse level. I’m partway there with this:
ourdb=> SELECT CASE
ourdb-> WHEN ASCII(c) < 65 THEN c::integer
ourdb-> ELSE ASCII(c)-65
ourdb-> END
ourdb-> FROM regexp_split_to_table('CNR39XL','') s(c);
case
------
2
13
17
3
9
23
11
(7 rows)
However, I can't figure out how to take that final set of numbers and convert it into the string. What am I looking for?
Use string_agg
SELECT CAST(
string_agg(
CAST (CASE ... END AS text),
''
)
AS numeric)
FROM ...
I have 2 varchar(64) values that are decimals in this case (say COLUMN1 and COLUMN2, both varchars, both decimal numbers(money)). I need to create a where clause where I say this:
COLUMN1 < COLUMN2
I believe I have to convert these 2 varchar columns to a different data types to compare them like that, but I'm not sure how to go about that. I tried a straight forward CAST:
CAST(COLUMN1 AS DECIMAL(9,2)) < CAST(COLUMN2 AS DECIMAL(9,2))
But I had to know that would be too easy. Any help is appreciated. Thanks!
You can create a UDF like this to check which values can't be cast to DECIMAL
CREATE OR REPLACE FUNCTION IS_DECIMAL(i VARCHAR(64)) RETURNS INTEGER
CONTAINS SQL
--ALLOW PARALLEL -- can use this on Db2 11.5 or above
NO EXTERNAL ACTION
DETERMINISTIC
BEGIN
DECLARE NOT_VALID CONDITION FOR SQLSTATE '22018';
DECLARE EXIT HANDLER FOR NOT_VALID RETURN 0;
RETURN CASE WHEN CAST(i AS DECIMAL(31,8)) IS NOT NULL THEN 1 END;
END
For example
CREATE TABLE S ( C VARCHAR(32) );
INSERT INTO S VALUES ( ' 123.45 '),('-00.12'),('£546'),('12,456.88');
SELECT C FROM S WHERE IS_DECIMAL(c) = 0;
would return
C
---------
£546
12,456.88
It really is that easy...this works fine...
select cast('10.15' as decimal(9,2)) - 1
from sysibm.sysdummy1;
You've got something besides a valid numerical character in your data..
And it's something besides leading or trailing whitespace...
Try the following...
select *
from table
where translate(column1, ' ','0123456789.')
<> ' '
or translate(column2, ' ','0123456789.')
<> ' '
That will show you the rows with alpha characters...
If the above does't return anything, then you've probably got a string with double decimal points or something...
You could use a regex to find those.
There is a built-in ability to do this without UDFs.
The xmlcast function below does "safe" casting between (var)char and decfloat (you may use as double or as decimal(X, Y) instead, if you want). It returns NULL if it's impossible to cast.
You may use such an expression twice in the WHERE clause.
SELECT
S
, xmlcast(xmlquery('if ($v castable as xs:decimal) then xs:decimal($v) else ()' passing S as "v") as decfloat) D
FROM (VALUES ( ' 123.45 '),('-00.12'),('£546'),('12,456.88')) T (S);
|S |D |
|---------|------------------------------------------|
| 123.45 |123.45 |
|-00.12 |-0.12 |
|£546 | |
|12,456.88| |
For a single value it works fine when I cast it to text:
WHERE product_id::text in (inputProduct_ids)
But I have problems if there is more than one value:
CREATE FUNCTION ourFunction(text) {
inputProduct_ids text := $1;
SELECT STRING_AGG(product_id::TEXT, ',' ORDER BY product_id)
INTO product_ids
FROM product_table
WHERE product_id in ('||inputProduct_ids||');
}
select ourFunction('573, 574 , 575 , 576 , 579 , 580 ,581 , 584');
If you really have to pass the argument as a string, you can cast it to an array of integer in the query:
SELECT string_agg(product_id::TEXT, ',' ORDER BY product_id)
INTO product_ids
FROM product_table
WHERE product_id =ANY (CAST('{' || $1 || '}' AS integer[]));
The =ANY operator can be used with arrays and does the same as IN (in fact the optimizer translates IN into =ANY internally).
As a_horse_with_no_name pointed out, you can also use string_to_array instead of a type cast:
WHERE CAST(product_id AS text) =ANY (string_to_array($1, ','))
Unfortunately, I have a table like the following:
DROP TABLE IF EXISTS my_list;
CREATE TABLE my_list (index int PRIMARY KEY, mystring text, status text);
INSERT INTO my_list
(index, mystring, status) VALUES
(12, '', 'D'),
(14, '[id] 5', 'A'),
(15, '[id] 12[num] 03952145815', 'C'),
(16, '[id] 314[num] 03952145815[name] Sweet', 'E'),
(19, '[id] 01211[num] 03952145815[name] Home[oth] Alabama', 'B');
Is there any trick to get out number of [id] as integer from the mystring text shown above? As though I ran the following query:
SELECT index, extract_id_function(mystring), status FROM my_list;
and got results like:
12 0 D
14 5 A
15 12 C
16 314 E
19 1211 B
Preferably with only simple string functions and if not regular expression will be fine.
If I understand correctly, you have a rather unconventional markup format where [id] is followed by a space, then a series of digits that represents a numeric identifier. There is no closing tag, the next non-numeric field ends the ID.
If so, you're going to be able to do this with non-regexp string ops, but only quite badly. What you'd really need is the SQL equivalent of strtol, which consumes input up to the first non-digit and just returns that. A cast to integer will not do that, it'll report an error if it sees non-numeric garbage after the number. (As it happens I just wrote a C extension that exposes strtol for decoding hex values, but I'm guessing you don't want to use C extensions if you don't even want regex...)
It can be done with string ops if you make the simplifying assumption that an [id] nnnn tag always ends with either end of string or another tag, so it's always [ at the end of the number. We also assume that you're only interested in the first [id] if multiple appear in a string. That way you can write something like the following horrible monstrosity:
select
"index",
case
when next_tag_idx > 0 then substring(cut_id from 0 for next_tag_idx)
else cut_id
end AS "my_id",
"status"
from (
select
position('[' in cut_id) AS next_tag_idx,
*
from (
select
case
when id_offset = 0 then null
else substring(mystring from id_offset + 4)
end AS cut_id,
*
from (
select
position('[id] ' in mystring) AS id_offset,
*
from my_list
) x
) y
) z;
(If anybody ever actually uses that query for anything, kittens will fall from the sky and splat upon the pavement, wailing in horror all the way down).
Or you can be sensible and just use a regular expression for this kind of string processing, in which case your query (assuming you only want the first [id]) is:
regress=> SELECT
"index",
coalesce((SELECT (regexp_matches(mystring, '\[id\]\s?(\d+)'))[1])::integer, 0) AS my_id,
status
FROM my_list;
index | my_id | status
-------+----------------+--------
12 | 0 | D
14 | 5 | A
15 | 12 | C
16 | 314 | E
19 | 01211 | B
(5 rows)
Update: If you're having issues with unicode handling in regex, upgrade to Pg 9.2. See https://stackoverflow.com/a/14293924/398670
I would like to convert an inet formatted IPv4 address into the integer components.
For example, turn '101.255.30.40' into oct1=101, oct2=255, oct3=30, and oct4=40.
There are regex expressions that should do this if I cast the inet as a varchar, but that seems inelegant. Is there a 1-line function for returning the nth octet of an inet?
select inet_to_octet('101.255.30.40', 4) as temp; -- returns temp=40?
I finally got an excellent answer from a co-worker...
For some flavors of sql, use "split_part" along with host(inet) to get the text field.
select split_part(host('101.255.30.40'::inet), '.', 1);
select split_part(host('101.255.30.40'::inet), '.', 2);
select split_part(host('101.255.30.40'::inet), '.', 3);
select split_part(host('101.255.30.40'::inet), '.', 4);
results in
101
255
30
40
If you want to get trickier and handle IPv6, use a mask to speed up the operation along with case statements to get the IP version:
select
(case
when family('101.255.30.40'::inet) = 4 then split_part(host(broadcast(set_masklen('101.255.30.40'::inet, 32))), '.', 4)::varchar
when family('101.255.30.40'::inet) = 6 then split_part(host(broadcast(set_masklen('101.255.30.40'::inet, 64))), ':', 4)::varchar
else null end)::varchar as octet4;
select
(case
when family('2604:8f00:4:80b0:3925:c69c:458:3f7b'::inet) = 4 then split_part(host(broadcast(set_masklen('2604:8f00:4:80b0:3925:c69c:458:3f7b'::inet, 32))), '.', 4)::varchar
when family('2604:8f00:4:80b0:3925:c69c:458:3f7b'::inet) = 6 then split_part(host(broadcast(set_masklen('2604:8f00:4:80b0:3925:c69c:458:3f7b'::inet, 64))), ':', 4)::varchar
else null end)::varchar as octet4;
results in
40
80b0
you can then add in a hex-to-int conversion into the case statement if you want to cast the IPv6 as a number instead.
Unless you want to try to contribute the function to the inet datatype, you'll need to rely on a string based version. Maybe put something like this (but with some error checking) into an SQL function for easy access?:
CREATE OR REPLACE FUNCTION extract_octet(inet, integer) RETURNS integer AS $$
SELECT ((regexp_split_to_array(host($1), E'\\.'))[$2])::int;
$$ LANGUAGE SQL;
select extract_octet(inet '192.26.22.2', 2)
Output: 26
Here are a couple of one-liners for the separate octets of an IPv4 address:
SELECT substring(host('1.2.3.4'::inet) FROM '^([0-9]+)\.[0-9]+\.[0-9]+\.[0-9]+$');
will return 1
SELECT substring(host('1.2.3.4'::inet) FROM '^[0-9]+\.([0-9]+)\.[0-9]+\.[0-9]+$');
will return 2
SELECT substring(host('1.2.3.4'::inet) FROM '^[0-9]+\.[0-9]+\.([0-9]+)\.[0-9]+$');
will return 3
SELECT substring(host('1.2.3.4'::inet) FROM '^[0-9]+\.[0-9]+\.[0-9]+\.([0-9]+)$');
will return 4