In this query the 'Daily' in the case will be replaced by a variable. I am not able to make this query work. I want to have the date column being either a day, a week a month or a year based on the value of the variable. but it is giving me various errors..
CASE types date and double precison cannot be matched
syntax error near "as"
what am I doing wrong?
select
case 'Daily'
when 'Daily' then DATE(to_timestamp(e.startts)) as "Date",
when 'Weekly' then DATE_PART('week',to_timestamp(e.startts)) as "Date",
when 'Monthly' then to_char(to_timestamp(e.startts), 'mm/yyyy') as "Date",
when 'Yearly' then to_char(to_timestamp(e.startts), 'yyyy') as "Date",
end
sum(e.checked)
from entries e
WHERE
e.startts >= date_part('epoch', '2020-10-01T15:01:50.859Z'::timestamp)::int8
and e.stopts < date_part('epoch', '2021-11-08T15:01:50.859Z'::timestamp)::int8
group by "Date"
CASE ... END is an expression. An expression must have a well-defined data type, so PostgreSQL makes sure that the expressions in the THEN clause have the same data type (or at least compatible ones).
You would need a type cast, probably to text, in the first two branches:
... THEN CAST (date(to_timestamp(e.startts)) AS text)
But it would be much better to use to_char in all branches – there are format codes for everything you need.
An expression can have no alias, only an entry in the SELECT or FROM list can. So you need to append AS "Date" at the end of the CASE ... END expression, not somewhere in the middle.
Related
select *
from nsclc_thought_spot
where patientid = 11000001
and service_date in ('2019-07-08', '2019-07-10')
order by patientid, service_date
is returning the results properly
But this is not working as expected:
select *
from nsclc_thought_spot
where patientid = 11000001
and service_date in (2019-07-08, 2019-07-10)
order by patientid, service_date
This query is not returning results.
If I have defined service_date column as date, then why do I have to pass the values in quotes inside IN operator in redshift?
Because 2019-07-08 means the integer 2019 minus the integer 7 minus the integer 8 which equals the integer 2004. Without quotes in SQL numbers are seen as numeric values. To be interpreted as something else you need to quote them (which is a text value) and then they need to be cast to the data type needed. In this case '2019-07-08' is a text value but Redshift will implicitly cast this to a date to make the comparison to the column data "service_date".
If you want to do this explicitly you can add the casting to the values - ... service_date IN ('2019-07-08'::date,'2019-07-10'::date) ... - which might make things clearer for you.
I get the following error for this query: [22P02] ERROR: invalid input syntax for type numeric: "."
select
date,
row_number () over () as RN,
case when (row_number() over ()) ='8' then '.' else (success/trials) end as "After_1M"
from trials
groupy by date;
Is there another way to indicate that a certain value in a ROWxCOLUMN combination should be adjusted?
Well your description certainly leaves a lot to be desired. But your query only needs slight modification to actually run. First off "groupy by date". I will assume it's just a typo. But a group by without an aggregate function generally doesn't do anything - and this is one of those. But I believe your attempting to get a row count by date. If so the you need the partition by and order by clauses in the in the row_number function. The other issue is in the expression. Each entry in the expression must return the same data type but in case it doesn't. The THEN condition returns character (.) while the ELSE returns a numeric (success/trials) which must define 2 numeric columns to be valid. So which needs to change? I will assume the later. Given this we wind up with:
select date
, row_number() over(partition by date order by trl_date) rn
, case when (row_number() over(partition by date order by trl_date)) = 8
then '.'
else (success/trials)::text
end as "After_1M"
from trials;
Note: Date is a very poor date is a very poor column name. It's a reserved word, as well as a data type.
I've got a column to import into an Azure SQL DB that is supposed to be made of dates only but of course contains errors.
In TSQL I would like to do something like: convert to date if it's possible otherwise null.
Does anyone know a statement to test the convertibility of a string into a date?
use TryCast or Isdate
select
try_Cast('test' as date)
select try_Cast('4' as date)
select case when ISDATE('test')=1 then cast('test' as date) else null end
TryCast will fail if the expression is not in expected format ..ie.,if the explicit conversion of expression is not permitted
select
try_cast( 4 as xml)
select try_Cast(4 as date)
You could use TRY_PARSE:
Returns the result of an expression, translated to the requested data type, or null if the cast fails. Use TRY_PARSE only for converting from string to date/time and number types.
SELECT TRY_PARSE('20129901' AS DATE)
-- NULL
Additionaly you could add culture:
SELECT TRY_PARSE('10/25/2015' AS DATE USING 'en-US')
And importing:
INSERT INTO target_table(date_column, ...)
SELECT TRY_PARSE(date_string_column AS DATE) ...
FROM source_table
...
I need to include EXTRACT() function within WHERE clause as follow:
SELECT * FROM my_table WHERE EXTRACT(YEAR FROM date) = '2014';
I get a message like this:
pg_catalog.date_part(unknown, text) doesn't exist**
SQL State 42883
Here is my_table content (gid INTEGER, date DATE):
gid | date
-------+-------------
1 | 2014-12-12
2 | 2014-12-08
3 | 2013-17-15
I have to do it this way because the query is sent from a form on a website that includes a 'Year' field where users enter the year on a 4-digits basis.
The problem is that your column is of data type text, while EXTRACT() only works for date / time types.
You should convert your column to the appropriate data type.
ALTER TABLE my_table ALTER COLUMN date TYPE date;
That's smaller (4 bytes instead of 11 for the text), faster and cleaner (disallows illegal dates and most typos).
If you have non-standard format add a USING clause with a conversion expression. Example:
Alter character field to date
Also, for your queries to be fast with a plain index on date you should rather use sargable predicates. Like:
SELECT * FROM my_table
WHERE date >= '2014-01-01'
AND date < '2015-01-01';
Or, to go with your 4-digit input for the year:
SELECT * FROM my_table
WHERE date >= to_date('2014', 'YYYY')
AND date < to_date('2015', 'YYYY');
You could also be more explicit:
to_date('2014' || '0101', 'YYYYMMNDD')
Both produce the same date '2014-01-01'.
Aside: date is a reserved word in standard SQL and a basic type name in Postgres. Don't use it as identifier.
This happens because the column has a text or varchar type, as opposed to date or timestamp. This is easily reproducible:
SELECT 1 WHERE extract(year from '2014-01-01'::text)='2014';
yields this error:
ERROR: function pg_catalog.date_part(unknown, text) does not exist
LINE 1: SELECT 1 WHERE extract(year from '2014-01-01'::text)='2014';
^ HINT: No function matches the given name and argument types. You might need to add explicit type casts.
extract or is underlying function date_part does not exist for text-like datatypes, but they're not needed anyway. Extracting the year from this date format is equivalent to getting the 4 first characters, so your query would be:
SELECT * FROM my_table WHERE left(date,4)='2014';
I have a problem with the query below in postgres
SELECT u.username,l.description,l.ip,SUBSTRING(l.createdate,0,11) as createdate,l.action
FROM n_logs AS l LEFT JOIN n_users AS u ON u.id = l.userid
WHERE SUBSTRING(l.createdate,0,11) >= '2009-06-07'
AND SUBSTRING(l.createdate,0,11) <= '2009-07-07';
I always used the above query in an older version of postgres and it worked 100%. Now with the new version of posgres it gives me errors like below
**ERROR: function pg_catalog.substring(timestamp without time zone, integer, integer) does not exist
LINE 1: SELECT u.username,l.description,l.ip,SUBSTRING(l.createdate,...
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.**
I assume it has something to do with datatypes, that the data is a time zone and that substring only support string datatypes, now my question is what can I do about my query so that my results would come up?
The explicit solution to your problem is to cast the datetime to string.
...,SUBSTRING(l.createdate::varchar,...
Now, this isn't at all a good practice to use the result to compare dates.
So, the good solution to your need is to change your query using the explicit datetime manipulation, comparison and formatting functions, like extract() and to_char()
You'd have to change your query to have a clause like
l.createdate::DATE >= '2009-06-07'::DATE
AND l.createdate::DATE < '2009-07-08'::DATE;
or one of the alternatives below (which you should really accept instead of this.)
SELECT u.username, l.description, l.ip,
CAST(l.createdate AS DATE) as createdate,
l.action
FROM n_logs AS l
LEFT JOIN
n_users AS u
ON u.id = l.userid
WHERE l.createdate >= '2009-06-07'::TIMESTAMP
AND l.createdate < '2009-07-07'::TIMESTAMP + '1 DAY'::INTERVAL
I'm not sure what you want to achieve, but basically "substring" on date datatypes is not really well defined, as it depends on external format of said data.
In most of the cases you should use extract() or to_char() functions.
Generally - for returning data you want to_char(), and for operations on it (including comparison) - extract(). There are some cases where this general rule does not apply, but these are usually signs of not really well thought data-structure.
Example:
# select to_char( now(), 'YYYY-MM-DD');
to_char
------------
2009-07-07
(1 row)
For extract let's write a simple query that will list all objects created after 8pm:
select * from objects where extract(hour from created) >= 20;
A variation on the Quassnoi's answer:
SELECT
u.username,
l.description,
l.ip,
CAST(l.createdate AS DATE) as createdate,
l.action
FROM
n_logs AS l
LEFT JOIN
n_users AS u
ON
(u.id = l.userid)
WHERE
l.createdate::DATE BETWEEN '2009-06-07'::DATE AND '2009-07-07'::DATE
If you use Postgresql, you will receive:
select('SUBSTRING(offer.date_closed, 0, 11)')
function substr(timestamp without time zone integer integer) does not
exist
Use:
select('SUBSTRING(CONCAT(offer.date_closed, \'\'), 0, 11)')