sql - Extract a date from a string

Question

I have a column description in my table with string value like this

"PK Event System Time: 31 January 2019 02:09  OK TO RIGOUR till 08:00 on Thursday Morning"

I need to extract the date part from this in SQL Server.

Expected output:

 31 January 2019 02:09

Answer 1

According to what you provide, you can simply use CHARINDEX() and SUBSTRING() functions as:

SELECT TRY_CAST(
       SUBSTRING(V, 
                 CHARINDEX(':', V)+2, 
                 CHARINDEX(':', V, CHARINDEX(':', V)+2) - CHARINDEX(':', V)+2
                ) AS DATETIME)
FROM
(
  VALUES
  ('PK Event System Time: 31 January 2019 02:09  OK TO RIGOUR till 08:00 on Thursday Morning'),
  ('Whatever: 01 Jun 2012 09:02  OK TO RIGOUR')
) T(V)

Note that the datetime should be always after ":". If it's not the case then please provide a good sample data.

Online Demo

Answer 2

The following works for your one example. I'm depending on the date starting after the first colon in the text string and then the time containing the second occurrence of a colon to locate the end of the date and time.

With TestValues AS
(
SELECT V.TextValue
FROM (VALUES
        ('PK Event System Time: 31 January 2019 02:09  OK TO RIGOUR till 08:00 on Thursday Morning')
     ) V(TextValue)

)
SELECT T.TextValue, TRY_CAST(DateString.DateString AS datetime) AS DateTimeVersion
FROM TestValues AS T
CROSS APPLY (SELECT NULLIF(CHARINDEX(':',T.TextValue),0) + 2 AS N) AS DateStart
CROSS APPLY (SELECT NULLIF(CHARINDEX(':',T.TextValue,DateStart.N),0) + 3 AS N) AS DateEnd
CROSS APPLY (SELECT SUBSTRING(T.TextValue,DateStart.N,DateEnd.N - DateStart.N) AS DateString) AS DateString

Answer 3

You can use CHARINDEX and SUBSTRING.

If "OK TO RIGOUR till" this String always present in your data then you check below query

select Trim( SUBSTRING(tbl.str, CHARINDEX(':',tbl.str) + 2 , (CHARINDEX('OK',tbl.str))  - (CHARINDEX(':',tbl.str) + 2))) from (SELECT V.str
FROM (VALUES
        ('PK Event System Time: 31 January 2019 02:09  OK TO RIGOUR till 08:00 on Thursday Morning')
     ) V(str)

  )tbl

http://sqlfiddle.com/#!18/9eecb/59559