I have used Excel and created 2 columns. column1 contains DATES, column2 contains values as INT. I have imported the table as a CSV using SQLite Manager. I am connected to the DB and have used it with success for other queries that involved text only. Now I would like to SELECT the INT in column2 that corresponds to the current date displayed in column1. Therefore, everyday when the SQL query is ran it will auto-update based on the new current date. I have used
SELECT column2 FROM table WHERE column1 = CURRENT_DATE
However, it returns null (blank, nothing), whereas if I use
SELECT column2 FROM table WHERE column1 > CURRENT_DATE
it returns the INT in column2 of rowid1, but if I use
SELECT column2 FROM table WHERE column1 < CURRENT_DATE
it returns the INT in column 2 of rowid3.
Therefore, the DB is functioning; however, the problem is it cannot associate the current system date with the right value in column1. Is it possible that the import of CSV. into SQLite has altered the datatype to VARCHAR or something other than DATE and INT?
SQLite does not have a DATE data type.
Dates are typically stored as strings (CSV does not have types anyway), and to be compatible with SQLite's built-in date functions, must be in the format yyyy-mm-dd.
Before exporting from Excel, ensure that all dates are formatted with this format.
Related
I was testing Sprak 3 upgrades in AWS Athena and need to check date columns whether timestamp format is proper or not,Can any one please give me query to check whether date columns has any Values other than Timestamp format
Assuming that you have a varchar column you can try using date_parse wrapped in try:
select *
from table
where try(date_parse(string_column, 'your_expected_format')) is null -- assuming no original nulls in column
Or via try_cast for "standard" format:
select *
from table
where try_cast(string_column as timestamp) -- assuming no original nulls in column
I have scenario as below: I have a table Tblbalance which contains a date and time column.
When I search using normal between clause in my stored procedure, it will throw error timeout in linq.
I tried to extend default time from 30 sec to 2 min in linq but not worked.
Please help me to get fastest way to return from select query
Sample query I tried is as below:
select
col1,
col2,
col3,
(select top 1 col from tblname where id = tblbalance.id)
from
tblbalance
where
datecol between startdate and todate
order by
col3
I would suggest to include one more column in you table and copy numeric of datetime in that column, Also create a index on the newly created numeric column. Then instead of using the datetime column in where clause, try using numeric column.
This way your query will run on index and will be optimised.
I have a query in a validation stored procedure. It goes something like this:
SELECT *
FROM Table1
WHERE batchID IN (SELECT id FROM #tempIds)
AND CAST(field1 AS DATE) > CAST(field2 AS DATE)
Both field1 and field2 have valid dates, i.e. doing IdDate on field1/2 returns 1.
The #tempIds table only has one column ID and contains only one row.
When I run the above query, I get this error:
Unable to convert varchar to date
But instead of selecting batch ids from temp table if I put hard-coded ID from the same temp table it works.
Any ideas what could be the issue?
The problem is that you are using varchar to store date (or datetime) values.
Choosing the correct data type for your columns would save you from a lot of problems, this one included. For detailed information, read Aaron Bertrand's Bad habits to kick : choosing the wrong data type.
Now, to address our conversation in the comments - SQL Server does not guarantee the order on which the conditions in the where clause are evaluated. This means that even if all the "date" strings in both your columns are convertible to date values for the specific batchID, you only need one wrong value in one of the columns to raise the "Unable to convert varchar to date" error.
This also means that even if you where to write your query the way Larry B suggested in his answer (now deleted - so for the sake of future readers - this was his suggestion:)
SELECT *
FROM Table1
WHERE batchID IN (SELECT id FROM #tempIds)
AND ISDATE(field1) = 1
AND ISDATE(field2) = 1
AND CAST(field1 AS DATE) > CAST(field2 AS DATE)
There is no guarantee that the last condition (cast(field1 as date) > cast(field2 as date)) will be evaluated after the isdate(field1)=1 condition.
The correct thing to do is to fix the problem - change the data types of the columns to the correct data type.
Assuming that can't be done (if you have no control over the structure of the database, for instance) - you can do a couple of things:
Find all the places where the values in field1 and in field2 can't be converted to dates and fix them. Consider adding a check constraint to validate that the values of these columns can be converted to date (assuming you can).
Separate your query into 2 parts:
;With cte as
(
SELECT *
FROM Table1
WHERE batchID IN (SELECT id FROM #tempIds)
AND ISDATE(field1) = 1
AND ISDATE(field2) = 1
)
SELECT *
FROM cte
WHERE CAST(field1 AS DATE) > CAST(field2 AS DATE)
This will eliminate the error, since you are only casting values where the ISDATE function already returned 1, but might not return some rows you want back, if the value if either field1 or field2 is wrong in these rows.
I'm inserting data into a table and before inserting I need to check if data exists.
I have a composite key consisted of two columns of datetime and int.
Before inserting I need to check if the data with the same time and id exists in the table.
The date that user is inserting is in 'mm/dd/yyyy'.
The datetime data in the table looks like this: '2016-01-12 00:00:00.000'.
The id field is int.
So, I have a query:
if not exists(select count(*) from table_1 where MyDate = #myDate and id = #id)
insert into table_1 .....
What is the right way to format the date user sends to match the datetime format in the table?
Check this sqlfiddle about how to use different date formats in your query. Might help you to solve it.
http://www.sqlfiddle.com/#!2/fd0b7/5
I am guessing that the question is about SQL Server, based on the syntax. The issues in the code snippet far transcend date formats.
First, the expression:
if not exists(select count(*) from table_1 where MyDate = #myDate and id = #id)
will never return true, because the subquery always returns one row with one column. If nothing matches, the column contains 0, which does exist.
You intend:
if not exists(select 1 from table_1 where MyDate = #myDate and id = #id)
Second, this check is not necessary if you wisely choose to have the database enforce the uniqueness constraint. So, define a unique index or constraint on the two columns:
create unique index unq_table_1_id_mydate on table_1(id, MyDate);
Now, the database won't let you insert duplicate values and no if is necessary.
Next, I would suggest that you fix the date format at the application layer. YYYY-MM-DD is an ISO standard date format and quite reasonable. However, if you don't want to do that, use convert():
insert into table_1(id, MyDate, .....)
select #id, convert(datetime, #MyDate, 101), . . .
The value in the database looks to be correct stored as a date/time value, so this should work fine.
You can use following line to convert date to required format in SQL server:
select FORMAT(#your_date, 'yyyy-MM-dd HH:mm:ss', 'en-US') from Your_Table
I have a column in Oracle DB which is varchar2 data type. Typical value stored in this column is like 06/16/2015 02:14:18 AM.
I am trying to get all records wherein this column is having records after 1st August 2015.
select *
from MYTABLE
where to_date(substr(MYCOLUMN,1,10),'dd-mm-yyyy') > to_date('01-08-2015','dd-mm-yyyy');
But, I am getting ORA-01843. Where am I doing wrong?
Respect the format in your VARCHAR
....where to_date(substr(MYCOLUMN,1,10),'mm/dd/yyyy')
I have a column in Oracle DB which is varchar2 data type. Typical value stored in this column is like 06/16/2015 02:14:18 AM.
The first question is why do you store DATE as string? Using appropriate data type is one of the most important part of database design and performance.
Understand that DATE doesn't have the format you see, it is internally stored in 7 bytes which is Oracle's proprietary format. Storing date as a string to have a fixed format is not recommended.
I would suggest first fix the design so that you don't have to do this overhead activity while comparing dates. In the longer run it will help you.
1. Add a new column as DATE data type.
ALTER TABLE table_name
ADD new_column DATE;
2. Update the new column.
UPDATE table_name
SET new_column = TO_DATE(old_column, 'mm/dd/yyyy hh:mi:ss pm');
3. DROP the old column.
ALTER TABLE table_name
DROP COLUMN old_column;
4. Rename the new column to old column name.
ALTER TABLE table_name
RENAME COLUMN old_name to new_name;
Now, you could compare dates easily:
SELECT * FROM MYTABLE WHERE mycolumn > to_date('01-08-2015','dd-mm-yyyy');
This will also use any regular index on the date column.
From performance point of view:
If you don't fix it now, you will keep facing performance issues. Because the immediate fix of SUBSTR will not let you use any regular index, you need to create a function-based index.
If in your table all values like 06/16/2015 02:14:18 AM then you can use trunc(to_date(MYCOLUMN,'mm/dd/yyyy HH:mi:SS PM'),'dd') against to_date(substr(MYCOLUMN,1,10),'dd-mm-yyyy').