I have questions regarding MySQL date and querying with it.
First:
SELECT * FROM post WHERE DATE(Post_Date)="2009-03-25"
returns 0 results
SELECT * FROM post WHERE Post_Date="2009-03-25"
returns 71 results
SELECT * FROM post WHERE Post_Date>="2009-03-25"
returns 379 results
I understand that the second query returning 71 results match only posts with 2009-03-25 00:00:00 as the Post_Date and the third query shows everything. BUT why does the first query SHOW 0 RESULTS?? Please help! I checked the MySQL cnf and the date_format is set to %Y-%m-%d
Second:
SELECT * FROM post WHERE DATE(Post_Date)="2009-03-25"
RETURNS results on WINDOWS!
SELECT * FROM post WHERE DATE(Post_Date)="2009-03-25"
NO RESULTS in Linux!
Any pointers will be helpful!
Is there a configuration file that I need to change to make this work in Linux?
Diagnostic step: run the query SELECT DATE('2009-03-25 08:30:00') on each system. The result will probably tell you what's going on. (Likely a version issue.)
Not sure what to day about your first part, but as for the second: Have you check to make sure that both your servers on windows and Linux have the same data in their respective databases? If you are sure that they are, you may want to check if the Linux database give any results for that year or year-month rather than only the specific year-month-date.
Related
Let's say I have the following 'items' table in my PostgreSQL database:
id
item
value
1
a
10
2
b
20
3
c
30
For some reason I can't control I need to run the following query:
select max(value) from items;
which will return 30 as the result.
At this point, I know that I can find the record that contains that value using simple select statements, etc. That's not the actual problem.
My real questions are:
Does PostgreSQL know (behind the scenes) what's is the ID of that
record, although the query shows only the max value of the column
'value'?
If yes, can I have access to that information and,
therefore, get the ID and other data from the found record?
I'm not allowed to create indexes and sequences, or change way the max value is retrieved. That's a given. I need to work from that point onward and find a solution (which I have, actually, from regular query work).
I'm just guessing that the database knows in which record that information (30) is and that I could have access to it.
I've been searching for an answer for a couple of hours but wasn't able to find anything.
What am I missing? Any ideas?
Note: postgres (PostgreSQL) 12.5 (Ubuntu 12.5-0ubuntu0.20.10.1)
You can simply extract the whole record that contains max(value) w/o bothering about Postgres internals like this:
select id, item, "value"
from items
order by "value" desc
limit 1;
I do not think that using undocumented "behind the scenes" ways is a good idea at all. The planner is smart enough to do exactly what you need w/o extra work.
I am trying to extract the time part only (excluding milliseconds) from the date-time string in amazon redshift.
I used:
Select now()::time;
But it is giving me error.
Error running query: Specified types or functions (one per INFO message) not supported on Redshift tables.
Any help would be highly appreciated.
I'm less sure about the error, but I agree with Jon Scott's comment, the following query runs fine without any error.
Select now()::time;
It outputs something like:
09:23:49.697401
It contains time with 6 digits after seconds.
If you just add time parameter up to, how many digits your need after seconds like below. Here its 0.
Select now()::time(0);
This will output:
09:23:49
If you do;
Select now()::time(1);
This will output:
09:23:49.6
Hope it answers your question.
Use below select clause returning the exact required result for time
Select CURRENT_TIME::time(0);
Halo,
first, i say thank you for helping me solve my problem before.
I'm really newbie using Postgresql.
now i have new problem,
i do select statement like this one :
select * from company where id=10;
when i see the query in pg_stat_statements, i just get the query like this :
select * from company where id=?;
from the result the value of id is missing,
how i can get the complete query without missing the value??
Thank you :)
Alternatively you could set log_min_duration to 0 which will lead Postgres to log every statement.
Pg_stat_statements is meant to be for stats and these are aggregated, if every lookup value would be in there the stats would be useless because it would be hard to group.
If you want to understand a query just run it with explain analyze and you will get the query plan.
I am running queries on an alarm system signal automation platform database in SQL Server 2012 Management Studio, and I am running into some hiccups.
My queries run just fine, but I am unable to refine my results to the level that I would like.
I am selecting some columns that are formatted as DATETIME, and I simply want to take the value in the column and subtract 4 hours from it (i.e., from GMT to EST) and then output that value into the query results.
All of the documentation I can find regarding DATESUB() or similar commands are showing examples with a specific DATETIME in the syntax, and I don't have anything specific, just 138,000 rows with columns I want to adjust time zones for.
Am I missing something big or will I just need to continue to adjust manually after I being manipulating my query result? Also, in case it makes a difference, I have a read-only access level, and am not interested in altering table data in any way.
Well, for starters, you need to know that you aren't restricted to use functions only on static values, you can use them on columns.
It seems that what you want is simply:
SELECT DATEADD(HOUR,-4,YourColumnWithDateTimes)
FROM dbo.YourTable
Maybe it will be helpful
SELECT DATEPART(HOUR, GETDATE());
DATEPART docs from MSDN
I am building a TSQL query to parse through a FTP log from FileZilla. I am trying to figure out if there is a way to get information from a line preceding the current one?
For example,
I have parsed out the Following procedure: "STOR file.exe"
With the FileZilla is doesn't say if the STOR wass successful until the next line. So I want to check the next line and see if the STOR was successful or was unsuccessful?
Also people could try to STOR a files multiple times so I want to get the last version of its status.
Example Info from Log file:
(000005) 4/10/2010 14:55:30 PM - ftp_login_name (IP Address)> STOR file.exe
(000005) 4/10/2010 14:55:30 PM - ftp_login_name (IP Address)> 150 Opening data for transfer.
(000005) 4/10/2010 14:55:30 PM - ftp_login_name (IP Address)> 226 Transfer OK
I want to add a column in my query that says that the STOR was successful or unsuccessful.
Thanks!
Assuming you have parsed these lines into actual columns, and you have SQL server 2005 or greater. You can use CROSS APPLY example query below (untested). I hope this helps.
select o.*, prev.*
from FTPLog o
cross apply
(
select top 1 *
from FTPLog P where P.LogDate < O.LogDate
order by LogDate DESC
) prev
James has the right idea, though there may be some issues if you ever have log dates that are exactly the same (and from your sample it looks like you might). You may be able to add an identity column to force an order at the time the data is inserted, then you can use James' concept on the identity column.
More than that though, TSQL may not be the best choice for this project, at least not by itself. While there are techniques you can use to make it iterate sequentially, it is not as good for that as certain other languages are. You may want to consider parsing your files in a tool, such as Python or Perl or even C#, that is better at text processing and better at processing data sequentially.