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Converting DB date in text format to date

I have a database in which the date fields were converted to text ( I inheirited the database). Now I would like to query the database, but the dates are stuck in text format. I need to convert them so I can compare date ranges in a query.

I'm using SQL Query Analyzer to test the SQL query string, and I get this message:

Server: Msg 306, Level 16, State 1, Line 3
The text, ntext, and image data types cannot be compared or sorted, except when using IS NULL or LIKE operator.

Is it possible to simply cast the text dates to temporarily make them dates for query purposes?

Please provite a simple SQL query for this.

Thanks!
Kittrick
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Kittrick
Asked:
Kittrick
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2 Solutions
 
Anthony PerkinsCommented:
>>Is it possible to simply cast the text dates to temporarily make them dates for query purposes?<<
Yes, but only if the format is well defined.  For example, assuming mm/dd/yyyy than the following should work:

CONVERT(datetime, CAST(YourDateColumn as varchar(10), 101)
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Brendt HessSenior DBACommented:
Unless you must leave the dates as text for some operational reason (e.g. other applications would break), I would convert the fields to varchar - things will be much cleaner then, since Text fields can only be converted to Varchar fields.

ALTER TABLE MyTable ALTER COLUMN DateAsText Varchar(<however long the date text actually is which depends on format>)

Otherwise, you will need to have a conversion like:

SELECT Cast(Cast(DateAsText As Varchar(100)) As DateTime) As DateAsDate
FROM MyTable

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Anthony PerkinsCommented:
Oops, that should have been:
CONVERT(datetime, CAST(YourDateColumn as varchar(10)), 101)
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KittrickAuthor Commented:
Thanks for your reply acperkins. How would I use it in the SQL query?

Here's my SQL statement:

SELECT ID, Start_date FROM database WHERE start_date>=1/1/2006

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Anthony PerkinsCommented:
If there is any chance that YourDateColumn is not valid than you will have to do something like this:

CASE
      WHEN ISDATE(CAST(@YourDateColumn as varchar(10))) = 1 THEN CONVERT(datetime, CAST(@YourDateColumn as varchar(10)), 101)
      ELSE Null
END
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Anthony PerkinsCommented:
Assuming they are all valid dates:

SELECT ID, Start_date
FROM database
WHERE CONVERT(datetime, CAST(start_date as varchar(10)), 101) >= '2006-01-01'
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KittrickAuthor Commented:
Thanks Bhess and acperkins! Both solutions worked, so I split the points evenly.

Kittrick
0

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