In Redshift we are trying to give more meaningful aliases to the columns we are returning from the queries as we are importing the results into TABLEAU, the issue is that RedShift turns all the letter to lower case ones, i.e. from "Event Date" it then returns "event date", any idea on how to work this one out to keep the alias given?
I know I'm a bit late to the party but for anyone else looking, you can enable case sensitivity, so if you want to return a column with camel casing for example
SET enable_case_sensitive_identifier TO true;
Then in your query wrap what you want to return the column as in double quotes
SELECT column AS "thisName"
Or as per OP's example
SELECT a.event_date AS "Event Date"
https://docs.aws.amazon.com/redshift/latest/dg/r_enable_case_sensitive_identifier.html
Edit: To have this behaviour as default for the cluster you will need to create/update a parameter group in Configurations => Workload Management. You can't change the settings for the default parameter group. Note, you will need to reboot the cluster after applying the parameter group for the changes to take effect.
No, you cannot do this in Redshift. all columns are lowercase only.
You can enforce upper case only by using
set describe_field_name_in_uppercase to on;
Also see the examples here https://docs.aws.amazon.com/redshift/latest/dg/r_names.html you can see that the upper case characters are returned as lower case. and it says "identifiers are case-insensitive and are folded to lowercase in the database"
You can of course rename the column to include uppercase within Tableau.
I was going through AWS docs for redshift and looks like INTCAP function can solve your use case
For reference => https://docs.aws.amazon.com/redshift/latest/dg/r_INITCAP.html
Brief description (copied)
The INITCAP function makes the first letter of each word in a string uppercase, and any subsequent letters are made (or left) lowercase. Therefore, it is important to understand which characters (other than space characters) function as word separators. A word separator character is any non-alphanumeric character, including punctuation marks, symbols, and control characters. All of the following characters are word separators:
! " # $ % & ' ( ) * + , - . / : ; < = > ? # [ \ ] ^ _ ` { | } ~
And in your case you have declared field name as event_date which will convert to Event_Date.
And next you can use REPLACE function to replace underscore '_'
For reference => https://docs.aws.amazon.com/redshift/latest/dg/r_REPLACE.html
You need to put
set describe_field_name_in_uppercase to on;
in your Tableau's Initial SQL.
Related
Postgresql 9.4: 1 column in 1 table is a string of text representing a route of flight for an aircraft.
The complete field consists of "Fixes" and "Routes" up to 80
characters in total length.
Routes and Fixes can be either 3 or 5 characters in length.
Routes and Fixes can have the same name.
There may be zero, one, or two Routes
Routes are followed by a single non-zero digit or a hash.
Routes and Fixes can be preceded or followed by a "+" or "*".
The field may contain CR/LF or double-triple spaces which should remain.
Each schema contains 6-20000s fields in this table
There are nearly 1800 Route names, but generally only 40-80 per schema
Examples:
"KIND ROCKY1 STL BUM OATHE CLASH5 KDEN"
"+MEARZ7 OKK+
KIND OKK FWA MIZAR3 KDTW"
"KIND OOM OOM5 WEGEE PXV J131 LIT BYP5 KDFW"
"KIND MEARZ# OKK ECK YEE YXI N171B VALIEE***EGSS"
The task is to clean up the lazy use of the hash instead of a digit and to update the Route versions (the trailing numbers). I.e. replace-in-place the Route with the correct digit rather than the # or what might be a wrong number. So every instance of "MEARZ7" or "MEARZ#" becomes "MEARZ9" and "OOM5" becomes "OOM6" but "OOM " stays "OOM ".
Currently I have been testing this:
UPDATE target SET detail =
CASE WHEN POSITION('CLASH' in detail) > 0
AND SUBSTRING(detail,POSITION('CLASH' in detail)+5,1) != ' '
THEN REGEXP_REPLACE (detail, 'CLASH.', 'CLASH5')
WHEN POSITION('MEARZ' in detail) > 0
AND SUBSTRING(detail,POSITION('MEARZ' in detail)+5,1) != ' '
THEN REGEXP_REPLACE (detail, 'MEARZ.', 'MEARZ9')
WHEN POSITION('OOM' in detail) > 0
AND SUBSTRING(detail,POSITION('OOM' in detail)+3,1) != ' '
THEN REGEXP_REPLACE (detail, 'OOM.', 'OOM6')
WHEN POSITION('ROCKY' in fsrtedtail) > 0
AND SUBSTRING(detail,POSITION('ROCKY' in detail)+5,1) != ' '
THEN REGEXP_REPLACE (detail, 'ROCKY.', 'ROCKY1')
ELSE detail END;
My logic was to:
Find the Route name.
Check if it's followed by a space.
If not, replace it with the correct Route+digit
I hadn't yet attempted to avoid "+" or "* ". I was thinking I could first replace the "#" with a number, then update the Route+digit as to not worry about the # and this would eliminate the need to look for the "+" or "* ". Then I could just look for a trailing space.
The second Route (in order of the WHEN statements) does not get updated so I guess am barking up the wrong tree.
They other big obstacle is there can be 80 or more Routes in a schema so if I have to nest a statement, it's gonna be huge.
I have tried array_to_string(array_replace(string_to_array( but it leaves behind double quotes, commas, and curly brackets so doesn't seem feasible.
At this point I'm thinking a function is the way to go, but I don't know where to start.
I have several PostgreSQL tables with "comment" columns (data type = text) for which I am trying to standardize the use of upper and lowercase. Specifically, I'd like to change the case of comment strings from all-caps to capitalization of only the first character in each sentence (there are typically 1-3 sentences per comment). I standardized the number of spaces between sentences (to 1) with
update table
set comment = regexp_replace(comment, '( ){2,}',' ','g');
and set all characters in each string except the first to lower case with
update table
set comment = upper(left(comment, 1)) || lower(right(comment, -1))
Now, how do I change the case of the first character after each period to uppercase? I can select the relevant characters with
select regexp_matches('Testing. this. using. some. text.', '([.]\s\S)', 'g');
but haven't been able to figure out how to capitalize these. Also, I'm sure there is a better way to conduct these steps in a more integrative way, but this is my noob-ish attempt.
The following worked in my situation, in which comments are made up of one or more sentences and sentences are separated by a period and single space:
with source as (
select regexp_split_to_table('hello. world', '\.\s') sentence
)
select array_to_string(
array(
select upper(left(sentence, 1)) || right(sentence, -1) sentence from source
), '. '
) modified_comment;
I have a DB2 v7r3 SQL SELECT statement with three instances of REGEXP_SUBSTR(), all with the same regex pattern string, each of which extract one of three groups.
I'd like to change the first SUBSTR to REGEXP_REPLACE() to do a conditional replacement if there's no match, to insert a default value similarly to the ELSE section of a CASE...END. But I can't make it work. I could easily use a CASE, but it seems more compact & efficient to use RegEx.
For example, I have descriptions of food containers sizes, in various states of completeness:
12X125
6X350
1X1500
1500ML
1000
The last two don't have the 'nnX' part at the beginning, in which case '1X' is assumed and needs to be inserted.
This is my current working pattern string:
^(?:(\d{1,3})(?:X))?((?:\d{1,4})(?:\.\d{1,3})?)(L|ML|PK|Z|)$
The groups returned are: quantity, size, and unit.
But only the first group needs the conditional replacement:
(?:(\d{1,3})(?:X))?
This RexEgg webpage describes the (?=...) operator, and it seems to be what I need, but I'm not sure. It's in the list of operators for my version of DB2, but I can't make it work. Frankly, it's a bit deeper than my regex knowledge, and I can't even make it work in my favorite online regex tester, Regex101.
So...does anyone have any idea or suggestions..? Thanks.
Try this (replace "digits not followed by X_or_digit"):
with t(s) as (values
'12X125'
, '6X350'
, '1X1500'
, '1500'
, '1125'
)
select regexp_replace(s, '^([\d]+(?![X\d]))', '1X\1')
from t;
I need to remove leading zeros and hyphens from a column value in Postgresql database, for example:
121-323-025-000 should look like 12132325
060579-0001 => 605791
482-322-004 => 4823224
timely help will be really appreciated.
Postgresql string functions.
For more advanced string editing, regular expressions can be very powerful. Be aware that complex regular expressions may not be considered maintainable by people not familiar with them.
CREATE TABLE testdata (id text, expected text);
INSERT INTO testdata (id, expected) VALUES
('121-323-025-000', '12132325'),
('060579-0001', '605791'),
('482-322-004', '4823224');
SELECT id, expected, regexp_replace(id, '(^|-)0*', '', 'g') AS computed
FROM testdata;
How regexp_replace works. In this case we look for the beginning of the string or a hyphen for a place to start matching. We include any zeros that follow that as part of the match. Next we replace that match with an empty string. Finally, the global flag tells us to repeat the search until we reach the end of the string.
I want to list the trigger no system ending with "_BI" in firebird database,
but no result with this
select * from rdb$triggers
where
rdb$trigger_source is not null
and (coalesce(rdb$system_flag,0) = 0)
and (rdb$trigger_source not starting with 'CHECK' )
and (rdb$trigger_name like '%BI')
but with this syntaxs it gives me a "_bi" and "_BI0U" and "_BI0U" ending result
and (rdb$trigger_name like '%BI%')
but with this syntaxs it gives me null result
and (rdb$trigger_name like '%#_BI')
thank you beforehand
The problem is that the Firebird system tables use CHAR(31) for object names, this means that they are padded with spaces up to the declared length. As a result, use of like '%BI') will not yield results, unless BI are the 30th and 31st character.
There are several solutions
For example you can trim the name before checking
trim(rdb$trigger_name) like '%BI'
or you can require that the name is followed by at least one space
rdb$trigger_name || ' ' like '%BI %'
On a related note, if you want to check if your trigger name ends in _BI, then you should also include the underscore in your condition. And as an underscore in like is a single character matcher, you need to escape it:
trim(rdb$trigger_name) like '%\_BI' escape '\'
Alternatively you could also try to use a regular expressions, as you won't need to trim or otherwise mangle the lefthand side of the expression:
rdb$trigger_name similar to '%\_BI[[:SPACE:]]*' escape '\'