I have an application that allows partial date searches. It doesn't specify what the date part is. if someone puts in "20", it could be part of the year or a day of the month.
The application uses an Access databases where some of the date fields have NULL values.
I am trying to write a query with [date field] LIKE {date criteria}.
What I started to do is convert the date field to a string using cstr(datefield), but the NULL values are giving #error values.
SELECT * ,cstr(datefield) AS strdate FROM table1
Access has the ISNULL function, but it only takes one parameter which returns true or false, as opposed to the ISNULL function in SQL Server, which takes two parameters, the second being the value to use if the first parameter is null.
I supposed I could add "AND datefield IS NOT NULL" to the end, but I wanted to ask if there were any other possible solutions to this.
Then when I did finally get to the query itself, it didn't return any results.
SELECT * ,cstr(datefield) AS strdate
FROM table1
WHERE scan_date IS NOT NULL
AND cstr(datefield) LIKE '%20%'
How would I do a LIKE query against a date field in access?
You can use the function Nz():
SELECT * , Nz(datefield) AS strdate
FROM table
WHERE Nz(datefield) LIKE '*20*'
But you should know that the wildcard operator to use in Access is not % but * and this is the reason that you don't get any results.
Related
Using Google BIGQUERY, I need to check that the values in a column called birth_day_col are the correct and desired date format: YYYY-MM-DD. The values in this column are defined as STRING. Also the values in this column are currently of the following format: YYYY-MM-DD.
I researched a lot on the internet and found an interesting workaround. The following query:
SELECT
DISTINCT birth_day_col
FROM `project.dataset.datatable`
WHERE birth_day_col LIKE '[1-2][0-9][0-9][0-9]/[0-1][0-9]/[0-3][0-9]'
AND country_code = 'country1'
But the result is: "This query returned no results."
I then checked with NOT, using the following code:
SELECT
DISTINCT birth_day_col
FROM `project.dataset.datatable`
WHERE NOT(birth_day_col LIKE '[1-2][0-9][0-9][0-9]/[0-1][0-9]/[0-3][0-9]')
AND country_code = 'country1'
Surprisingly it gave all the values in birth_dat_col, which I have verified and are of the correct date format, but this result coud very much be a coincidence.
And it is very strange (wrong) that I used a query that should result only the wrong format dates, but it actually gives me the correct ones. Everything about these two queries seems like an inversation of each one's role.
The expected result of any query for this business case is to make a count of all incorrect formatted dates (even if currently this is 0).
Thank you for your help!
Robert
A couple of things here:
Read the documentation for the LIKE operator if you want to understand how to use it. It looks like you're trying to use regular expression syntax, but the LIKE operator does not take a regular expression as input.
The standard format for BigQuery's dates is YYYY-MM-DD, so you can just try casting and see if the result is a valid date, e.g.:
SELECT SAFE_CAST(birth_day_col AS DATE) AS birth_day_col
FROM `project`.dataset.table
This will return null for any values that don't have the correct format. If you want to find all of the ones that don't have the correct format, you can use SAFE_CAST inside a filter:
SELECT DISTINCT birth_day_col AS invalid_date
FROM `project`.dataset.table
WHERE SAFE_CAST(birth_day_col AS DATE) IS NULL
The result of this query will be all of the date strings that don't use YYYY-MM-DD format. If you want to check for slashes instead, you can use REGEXP_CONTAINS, e.g. try this:
SELECT
date,
REGEXP_CONTAINS(date, r'^[0-9]{4}/[0-9]{2}/[0-9]{2}$')
FROM (
SELECT '2019/05/10' AS date UNION ALL
SELECT '2019-05-10' UNION ALL
SELECT '05/10/2019'
)
If you want to find all dates with either YYYY-MM-DD format or YYYY/MM/DD format, you can use a query like this:
SELECT
DISTINCT date
FROM `project`.dataset.table
WHERE REGEXP_CONTAINS(date, r'^[0-9]{4}[/\-][0-9]{2}[/\-][0-9]{2}$')
For example:
SELECT
DISTINCT date
FROM (
SELECT '2019/05/10' AS date UNION ALL
SELECT '2019-05-10' UNION ALL
SELECT '05/10/2019'
)
WHERE REGEXP_CONTAINS(date, r'^[0-9]{4}[/\-][0-9]{2}[/\-][0-9]{2}$')
Yet another example for BigQuery Standrad SQL - with use of SAFE.PARSE_DATE
#standardSQL
WITH `project.dataset.table` AS (
SELECT '1980/08/10' AS birth_day_col UNION ALL
SELECT '1980-08-10' UNION ALL
SELECT '08/10/1980'
)
SELECT birth_day_col
FROM `project.dataset.table`
WHERE SAFE.PARSE_DATE('%Y-%m-%d', birth_day_col) IS NULL
with result of list of all dates which are not formatted as yyyy-mm-dd
Row birth_day_col
1 1980/08/10
2 08/10/1980
Google BigQuery's LIKE operator does not support matching digits nor does it uses the [ character in its syntax (I don't think ISO standard SQL does either - LIKE is nowhere near as powerful as Regex).
X [NOT] LIKE Y
Checks if the STRING in the first operand X matches a pattern specified by the second operand Y. Expressions can contain these characters:
A percent sign "%" matches any number of characters or bytes
An underscore "_" matches a single character or byte
You can escape "\", "_", or "%" using two backslashes. For example, "\%". If you are using raw strings, only a single backslash is required. For example, r"\%".
You should use REGEX_CONTAINS instead.
I note that string format tests won't tell you if a date is valid or not, however. Consider that 2019-02-31 has a valid date format, but an invalid date value. I suggest using a datatype conversion function (to convert the STRING to a DATE value) instead.
I am vb.net newbie and working on a program which will be used as a daily-worklog. As backend I use MS ACCESS. I store the "datetime.utc.now" time in a field (type:date/time) of MS Access.
This is shown in the database like: dd.mm.yyyy hh:mm:ss
I want to see all entered items of the last 12 hours. I used many different ways, but I´m not able to fix it.
My preferred / logical (for me :-)) way to do this was:
add the parameter:
mycommand.SelectCommand.Parameters.AddWithValue("date12",OleDbType.DBTimeStamp).Value = DateTime.UtcNow.AddHours(-12)
Query the database
select * from complaints where entrydate >= #date12;
But I can't figure out why it doesn't work.
Failure message = "data types in criteria expression incompatible"
I assume the problem is the different time formats, but I'm not sure and I have no clue how I could fix it.
MS Access does not use named parameters. You use a ? for all of the placeholders in the SQL statement. You still can and should give the parameter object a name, but the value is matched to the placeholder based on position in the Parameters collection and query string rather than name.
SQL:
"select * from complaints where entrydate >= ?;"
VB:
mycommand.SelectCommand.Parameters.Add("date12",OleDbType.Date).Value = DateTime.UtcNow.AddHours(-12)
Do NOT settle for hard-coding the parameter value. What you can do is use SQL expressions to determine the date value, and avoid both parameters and string concatentation:
select * from complaints where entrydate >= DATEADD('h', -12, Now())
You can change the type to OleDbType.Date or hardcode the query:
select * from complaints where entrydate >= ( Now() - 0.5 )
Trouble inserting DateTime into Access with OleDb
As a side note, most value types are generally safe to hardcode:
"select * from complaints where entrydate >= " & DateTime.UtcNow.AddHours(-12).ToOADate()
I'm a B-grade SQL user, so bear with me. I have a field that is in the NVARCHAR format ("Year"), but all but only about 1 in 1000 records is something other than a number. Yes, this is a ridiculous way to do this, but we receive this database from a customer, and we can't change it.
I want to pull records from the database where the year field is greater than something (say, 2006 or later). I can ignore any record whose year doesn't evaluate to an actual year. We are using SQL server 2014.
I have created an embedded query to convert the data to a "float" field, but for whatever reason, I can't add a where clause with this new floating-point field. I originally tried using a "case-if" but I got the same result.
I'm pulling my hair out, as I'm either missing something really silly, or there's a bug in SQL server. When I look at the field in the little hint, it's showing as a float. When I run this, I get "Error converting data type nvarchar to float."
SELECT VL.Field_A,
VL.FLYear,
VL.Field_B
FROM
(select
Field_A,
cast ([Year] as float) as FLYear,
/* didn't work either*/
/*Convert(float, [Year]) as FLYear, */
Field_B
from CustomerProvidedDatabaseTable
where (Field_A like 'E-%' OR
Field_A like 'F-%')
and
(isnumeric(year)=1)
and
year is not null
) VL
/* this statement is the one it chokes on */
where
VL.FLYear >= 2006.0
If I remove the last "where" clause, it works fine, and the field looks like a number. If I change the last where clause to:
where VL.FLYear like '%2006%'
SQL Server accepts it, though of course it doesn't return me all the records I want.
Try to simplify it and just use TRY_CONVERT(DATETIME, aYearvalue) or TRY_PARSE which will return NULL for values it can't convert and continue to process valid rows. I think you can do away with the where clause as join and just work directly against the column like: (substitute the literal string after datetime with your column)
SET DATEFORMAT mdy;
Select YEAR(try_convert(datetime, '08/01/2017')) as value1
WHERE value1 >=2016;
Try cast/convert to a numeric data type. I have modified the last line of your query to do just that. Take a peek.
SELECT
VL.Field_A,
VL.FLYear,
VL.Field_B
FROM
(select
Field_A,
cast ([Year] as float) as FLYear,
/* didn't work either*/
/*Convert(float, [Year]) as FLYear, */
Field_B
from CustomerProvidedDatabaseTable
where (Field_A like 'E-%' OR
Field_A like 'F-%')
and
(isnumeric(year)=1)
and
year is not null
) VL
/* this statement is the one it chokes on */
where
ISNUMERIC(VL.FLYear) = 1
and
CAST(VL.FLYear AS INT) >= 2006
Check out the following link for cast and convert documentation:
https://learn.microsoft.com/en-us/sql/t-sql/functions/cast-and-convert-transact-sql
NOTE: ISNUMERIC will return true ( a false positive for a value which has a scientific numerical value, e.g. 1E10, though I don't see this happening from your data).
Another option is TRY_CONVERT.
Documentation on TRY_CONVERT: https://learn.microsoft.com/en-us/sql/t-sql/functions/try-convert-transact-sql
Try using Cast . Use the below link to check in more detail about casting.
https://learn.microsoft.com/en-us/sql/t-sql/functions/cast-and-convert-transact-sql
I have a table and need to verify that a certain column contains only dates. I'm trying to count the number of records that are not follow a date format. If I check a field that I did not define as type "date" then the query works. However, when I check a field that I defined as a date it does not.
Query:
SELECT
count(case when ISDATE(Date_Field) = 0 then 1 end) as 'Date_Error'
FROM [table]
Column definition:
Date_Field(date, null)
Sample data: '2010-06-27'
Error Message:
Argument data type date is invalid for argument 1 of isdate function.
Any insight as to why this query is not working for fields I defined as dates?
Thanks!
If you defined the column with the Date type, it IS a Date. Period. This check is completely unnecessary.
What you may want to do is look for NULL values in the column:
SELECT SUM(case when Date_Field IS NULL THEN 1 ELSE 0 end) as 'Date_Error' FROM [table]
I also sense an additional misunderstanding about how Date fields, including DateTime and DateTime2, work in Sql Server. The values in these fields are not stored as a string in any format at all. They are stored in a binary/numeric format, and only shown as a string as a convenience in your query tool. And that's a good thing. If you want the date in a particular format, use the CONVERT() function in your query, or even better, let your client application handle the formatting.
ISDATE() only evaluates against a STRING-like parameter (varchar, nvarachar, char,...)
To be sure, ISDATE()'s parameter should come wrapped in a cast() function.
i.e.
Select isdate(cast(parameter as nvarchar))
should return either 1 or 0, even if it's a MULL value.
Hope this helps.
IsDate takes a character string or exression that yeilds a character string as it's argument
The problem is this method ISDATE() only admits arguments of type datetime and smalldatetime within the "time" types, so it won´t work if you are using date type.
Also if you use date as type for that field, you won´t have to check the information there because it won´t admit other type of field.
You shoul only check for null values in your column, that´s all.
I've been tasked to take a calendar date range value from a form front-end and use it to, among other things, feed a query in a Teradata table that does not have a datetime column. Instead the date is aggregated from two varchar columns: one for year (CY = current year, LY = last year, LY-1, etc), and one for the date with format MonDD (like Jan13, Dec08, etc).
I'm using Coldfusion for the form and result page, so I have the ability to dynamically create the query, but I can't think of a good way to do it for all possible cases. Any ideas? Even year differences aside, I can't think of anything outside of a direct comparison on each day in the range with a potential ton of separate OR statements in the query. I'm light on SQL knowledge - maybe there's a better way to script it in the SQL itself using some sort of conversion on the two varchar columns to form an actual date range where date comparisons could then be made?
Here is some SQL that will take the VARCHAR date value and perform some basic manipulations on it to get you started:
SELECT CAST(CAST('Jan18'||TRIM(EXTRACT(YEAR FROM CURRENT_DATE)) AS CHAR(9)) AS DATE FORMAT 'MMMDDYYYY') AS BaseDate_
, CASE WHEN Col1 = 'CY'
THEN BaseDate_
WHEN Col1 = 'LY'
THEN ADD_MONTHS(BaseDate_, -12)
WHEN Col1 = 'LY-1'
THEN ADD_MONTHS(BaseDate_, -24)
ELSE BaseDate_
END AS DateModified_
FROM {MyDB}.{MyTable};
The EXTRACT() function allows you to take apart a DATE, TIME, or TIMESTAMP value.
You have you use TRIM() around the EXTRACT to get rid of the whitespace that is added converting the DATEPART to a CHAR data type. Teradata is funny with dates and often requires a double CAST() to get things sorted out.
The CASE statement simply takes the encoded values you suggested will be used and uses the ADD_MONTHS() function to manipulate the date. Dates are INTEGER in Teradata so you can also add INTEGER values to them to move the date by a whole day. Unlike Oracle, you can't add fractional values to manipulate the TIME portion of a TIMESTAMP. DATE != TIMESTAMP in Teradata.
Rob gave you an sql approach. Alternatively you can use ColdFusion to generate values for the columns you have. Something like this might work.
sampleDate = CreateDate(2010,4,12); // this simulates user input
if (year(sampleDate) is year(now())
col1Value = 'CY';
else if (year(now()) - year(sampleDate) is 1)
col1Value = 'LY'
else
col1Value = 'LY-' & DateDiff("yyyy", sampleDate, now());
col2Value = DateFormat(sampleDate, 'mmmdd');
Then you send col1Value and col2Value to your query as parameters.