I'm trying to do a query like this on a table with a DATETIME column.
SELECT * FROM table WHERE the_date =
2011-03-06T15:53:34.890-05:00
I have the following as an string input from an external source:
2011-03-06T15:53:34.890-05:00
I need to perform a query on my database table and extract the row which contains this same date. In my database it gets stored as a DATETIME and looks like the following:
2011-03-06 15:53:34.89
I can probably manipulate the outside input slightly ( like strip off the -5:00 ). But I can't figure out how to do a simple select with the datetime column.
I found the convert function, and style 123 seems to match my needs but I can't get it to work. Here is the link to reference about style 123
http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.ase_15.0.blocks/html/blocks/blocks125.htm
I think that convert's slightly wrongly documented in that version of the docs.
Because this format always has century I think you only need use 23. Normally the 100 range for convert adds the century to the year format.
That format only goes down to seconds what's more.
If you want more you'll need to past together 2 x converts. That is, past a ymd part onto a convert(varchar, datetime-column, 14) and compare with your trimmed string. milliseconds comparison is likely to be a problem depending on where you got your big time string though because the Sybase binary stored form has a granularity of 300ms I think, so if your source string is from somewhere else it's not likely to compare. In other words - strip the milliseconds and compare as strings.
So maybe:
SELECT * FROM table WHERE convert(varchar,the_date,23) =
'2011-03-06T15:53:34'
But the convert on the column would prevent the use of an index, if that's a problem.
If you compare as datetimes then the convert is on the rhs - but you have to know what your milliseconds are in the_date. Then an index can be used.
Related
I'm using a SQLite3 database, and I have a table that looks like this:
The database is quite big and running queries is very slow. I'm trying to speed up the process by indexing some of the columns. One of the columns that I want to index is the QUOTE_DATETIME column.
Problem: I want to index by date (YYYY-MM-DD) only, not by date and time (YYYY-MM-DD HH:MM:SS), which is the data I currently have in QUOTE_DATETIME.
Question: How can I use CREATE INDEX to create an index that uses only dates in the format YYYY-MM-DD? Should I split QUOTE_DATETIME into 2 columns: QUOTE_DATE and QUOTE_TIME? If so, how can I do that? Is there an easier solution?
Thanks for helping! :D
Attempt 1: I tried running CREATE INDEX id ON DATA (date(QUOTE_DATETIME)) but I got the error Error: non-deterministic functions prohibited in index expressions.
Attempt 2: I ran ALTER TABLE data ADD COLUMN QUOTE_DATE TEXT to create a new column to hold the date only. And then INSERT INTO data(QUOTE_DATE) SELECT date(QUOTE_DATETIME) FROM data. The date(QUOTE_DATETIME) should convert the date + time to only date, and the INSERT INTO should add the new values to QUOTE_DATE. However, it doesn't work and I don't know why. The new column ends up not having anything added to it.
Expression indexes must not use functions that might change their return value based on data not mentioned in the function call itself. The date() function is such a function because it might use the current time zone setting.
However, in SQLite 3.20 or later, you can use date() in indexes as long as you are not using any time zone modifiers.
INSERT adds new rows. To modify existing rows, use UPDATE:
UPDATE Data SET Quote_Date = date(Quote_DateTime);
What is wrong with my code:
ExecSql('DELETE FROM STLac WHERE RegN=99 AND BegDate>= 2016-12-14');
This runs, but deletes ALL the rows in STLac for RegN, not just the rows with BegDate on or after 2016-12-14.
Originally I had:
ExecSql('DELETE FROM STLac WHERE RegN=99 AND BegDate>= :myDdate,[myDate]);
which has the advantage I hoped of not being particular to the date format. So I tried the literal date should in the format SQLite likes. Either way I get all rows deleted, not just those on or after the specified date.
Scott S.
Try double quote while putting date. As any value must be provided in between quotes until and unless that column is not int
ExecSql('DELETE FROM STLac WHERE RegN=99 AND BegDate>= "2016-12-14"');
SQLite does not have datetime format as such, so you have to figure out how date is actually represented in the table and change your query to provide the same format. First execute the "select" statement in some kind of management tool,
select * from STLac where RegN = 99 and BegDate >= '2016-12-14' --(or '2016.12.04' or something else)
which displays the result in the grid; when you see the expected rows, change it to "delete" query and copy into your Delphi program.
I insert my date/time data into a CHAR column in the format: '6/4/2015 2:08:00 PM'.
I want that this should get automatically converted to format:
'2015-06-04 14:08:00' so that it can be used in a query because the format of DATETIME is YYYY-MM-DD hh:mm:ss.fffff.
How to convert it?
Given that you've stored the data in a string format (CHAR or VARCHAR), you have to decide how to make it work as a DATETIME YEAR TO SECOND value. For computational efficiency, and for storage efficiency, it would be better to store the value as a DATETIME YEAR TO SECOND value, converting it on input and (if necessary) reconverting on output. However, if you will frequently display the value without doing computations (including comparisons or sorting) it, then maybe a rococo locale-dependent string notation is OK.
The key function for converting the string to a DATETIME value is TO_DATE. You also need to look at the TO_CHAR function because that documents the format codes that you need to use, and because you'll use that to convert a DATETIME value to your original format.
Assuming the column name is time_string, then you need to use:
TO_DATE(time_string, '%m/%d/%Y %I:%M %x') -- What goes in place of x?
to convert to a DATETIME YEAR TO SECOND — or maybe DATETIME YEAR TO MINUTE — value (which will be further manipulated as if by EXTEND as necessary).
I would personally almost certainly convert the database column to DATETIME YEAR TO SECOND and, when necessary, convert to the string format on output with TO_CHAR. The column name would now be time_value (for sake of concreteness):
TO_CHAR(time_value, '%m/%d/%Y %I:%M %x') -- What goes in place of x?
The manual pages referenced do not immediately lead to a complete specification of the format strings. I think a relevant reference is GL_DATETIME environment variable, but finding that requires more knowledge of the arcana of the Informix product set than is desirable (it is not the first thing that should spring to anyone's mind — not even mine!). If that's correct (it probably is), then one of %p and %r should be used in place of %x in my examples. I have to get Informix (re)configured on my machine to be able to test it.
I am reading a big csv (>1GB big for me!). It contains a timestamp field.
I read it (100 rows to start with ) with fread from the excellent data.table package.
ddfr <- fread(input="~/file1.csv",nrows=100, header=T)
Problem 1 (RESOLVED): the timestamp fields (called "ts" and "update"), e.g. "02/12/2014 04:40:00 AM" is converted to string. I convert the fields back to timestamp with lubridate package mdh_hms. Splendid.
ddfr$ts <- data.frame( mdy_hms(ddfr$ts))
Problem 2 (NOT RESOLVED): The timestamp is created with time zone as per POSIXlt.
How do I create in R a timestamp with NO TIME ZONE? is it possible??
Now I use another (new) great package, PivotalR to write the dataframe to PostGreSQL 9.3 using as.db.data.frame. It works as a charm.
x <- as.db.data.frame(ddfr, table.name= "tbl1", conn.id = 1)
Problem 3 (NOT RESOLVED): As the original dataframe timestamp fields had time zones, a table is created with the fields "timestamp with time zone". Ultimately the data needs to be stored in a table with fields configured as "timestamp without time zone".
But in my table in Postgres the data is stored as "2014-02-12 04:40:00.0", where the .0 at the end is the UTC offset. I think I need to have "2014-02-12 04:40:00".
I tried
ALTER TABLE tbl ALTER COLUMN ts type timestamp without time zone;
Then I copied across. While Postgres accepts the ALTER COLUMN command, when I try to copy (using INSERT INTO tbls SELECT ...) I get an error:
"column "ts" is of type timestamp without time zone but expression is of type text
Hint: You will need to rewrite or cast the expression."
Clearly the .0 at the end is not liked (but why then Postgres accepts the ALTER COLUMN? boh!).
I tried to do what the error suggested using CAST in the INSERT INTO query:
INSERT INTO tbl2 SELECT CAST(ts as timestamp without time zone) FROM tbl1
But I get the same error (including the suggestion to use CAST aargh!)
The table directly created by PivotalR (based on the dataframe) has this CREATE script:
CREATE TABLE tbl2
(
businessid integer,
caseno text,
ts timestamp with time zone
)
WITH (
OIDS=FALSE
);
ALTER TABLE tbl1
OWNER TO mydb;
The table I'm inserting into has this CREATE script:
CREATE TABLE tbl1
(
id integer NOT NULL DEFAULT nextval('bus_seq'::regclass),
businessid character varying,
caseno character varying,
ts timestamp without time zone,
updated timestamp without time zone,
CONSTRAINT busid_pkey PRIMARY KEY (id)
)
WITH (
OIDS=FALSE
);
ALTER TABLE tbl1
OWNER TO postgres;
My apologies for the convoluted explanation, but potentially a solution could be found at any step in the chain, so I preferred to put all my steps in one question. I am sure there has to be a simpler method...
I think you're confused about copying data between tables.
INSERT INTO ... SELECT without a column list expects the columns from source and destination to be the same. It doesn't magically match up columns by name, it'll just assign columns from the SELECT to the INSERT from left to right until it runs out of columns, at which point any remaining cols are assumed to be null. So your query:
INSERT INTO tbl2 SELECT ts FROM tbl1;
isn't doing this:
INSERT INTO tbl2(ts) SELECT ts FROM tbl1;
it's actually picking the first column of tbl2, which is businessid, so it's really attempting to do:
INSERT INTO tbl2(businessid) SELECT ts FROM tbl1;
which is clearly nonsense, and no casting will fix that.
(Your error in the original question doesn't match your tables and queries, so the details might be different as you've clearly made a mistake in mangling/obfuscating your tables or posted a newer version of the tables than the error. The principle remains.)
It's generally a really bad idea to assume your table definitions won't change and column order won't change anyway. So always be explicit about columns. In this case I think your intention might have actually been:
INSERT INTO tbl2(businessid, caseno, ts)
SELECT CAST(businessid AS integer), caseno, ts
FROM tbl1;
Note the cast, because the type of businessid is different between the two tables.
I´m new to MDX and I have a simple question. I work with the TFS Cube it is named as Team System. My problem:
I have an IIF expression where I want to check additional my expression with an AND operator. There I want to compare two DateTime objects. The report should only show me the data from the actual date. Here my code:
IIF(ISEMPTY(SUM(YTD(
[Work Item].[PlannedWeek__HierarchyByWeek].CurrentMember),
[Measures].[EffectivelyValue]))
AND[Work Item].[PlannedWeek__HierarchyByWeek].CurrentMember < Now()
, [Measures].[EffectivelyValue]
, SUM(YTD(
[Work Item].[PlannedWeek__HierarchyByWeek].CurrentMember),
[Measures].[EffectivelyValue]) )
Planned Week is a self created field which has the DateTime datatype. The Now() function has also a DateTime datatype so the comparision should be right but it happens nothing.
Thanking you in anticipation
Eugen
Hierarchy members in MDX have a data type of 'member', and do not have a 'primitive' data type like datetime, string, or integer. Only member properties have 'primitive' data types. You could either define a property like datetime of your week attribute. Assuming you are SQL Server Analysis Services, this would be done via relationships.
Or you could use string operations to extract the date information from the UniqueName property which avoids having to change the cube. The UniqueName contains the data that you defined as the key in your cube design. Assuming your week hierarchy members have a key from which you can extract something like 20130820 for August 20, 3013 via string functions (I just will use Mid(, 30, 8) as an example below), you could do something like
CLng(Mid([Work Item].[PlannedWeek__HierarchyByWeek].CurrentMember.UniqueName, 30, 8))
<
CLng(Format(Now(), "yyyymmdd"))
You will have to check what exactly the CurrentMember.UniqueName shows in your cube to adapt the above code.
And finally, you could of course also use string methods to extract the relevant parts from the UniqueName and then the CDate function on that to compare to an unchanged Now(), i. e. do all operations on the left side of the <.
Hello thank you very much for you answer. I tried:
Mid([Work Item].[xxxx_PlannedWeek__HierarchyByWeek].CurrentMember.UniqueName,58,10)
shows e.g. 2013-07-21, 2013-07-28 (it shows the week endings)
so I tried this:
AND CLng(Mid([Work Item].[xxxx_PlannedWeek__HierarchyByWeek].CurrentMember.UniqueName,58,10))
<CLng(Format(Now(), "yyyy-mm-dd"))
But it happens nothing. If I execute it in a single way it shows everywhere "true". But I have datasets with dates which are e.g. > 2013-08-23. So there should be false values too.
EDIT: OK I solved the problem. The
Format(Now(), "yyyy-mm-dd")
must be
Format(Now(), "yyyy-MM-dd")