How do I get a substring out from a string?

  • We're storing some data from our Active Directory network into a table. There are 2 columns which are the most interesting. One is for the employee and the other is for the employee's supervisor, which is called ADManager. (That might be the name of the field in AD, I don't really know.) The issue is that the values that the extract from AD gives us is the full CN record from AD, but we have to only store just the employee's manager's name. For example, this is what is coming out of AD for a manager whose name is John Smith:

    CN=John Smith,OU=Production,OU=IT,OU=Santa Fe,OU=Region 2,DC=doh,DC=state,DC=nm,DC=us

    What we want to store in the ADManager field of the table is just "John Smith". My problem is that my SQL skills aren't up to retrieving just "John Smith" from the field. I know how to find such records using the wild card character %:

    SELECT * FROM ADTable WHERE ADManager like 'CN=%,OU=%'

    But that will just give me the whole record with the whole ADManager field. How do I pare it down to just "John Smith"?

    BTW, in looking at the data in the ADTable, I've seen that the manager's name (and employee's name, too) is either like this:

    FirstName LastName

    Or it is like this:

    FirstName.LastName

    Although AD allows for this:

    LastName, FirstName

    our system admins must not be storing it like LastName, FirstName in AD, so I don't have to concern myself with the embedded comma.

    Kindest Regards, Rod Connect with me on LinkedIn.

  • I would use CHARINDEX to look for the start and end of the section you need, and then use the substring function around that.

    DECLARE @string VARCHAR(256) = 'CN=John Smith,OU=Production,OU=IT,OU=Santa Fe,OU=Region 2,DC=doh,DC=state,DC=nm,DC=us';

    SELECT SUBSTRING(@string, CHARINDEX('CN=', @string) + 3,

    CHARINDEX(',OU=', @string) - 4);



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  • What Nicholas proposed will work provided that CN= always comes before OU=. Working with AD, I've see that this is not always the case. If this is how it is in your environment then that's the way to go.

    Provided you don't have CN=Lastname,Firstname in your table you could use DelimitedSplit8K_LEAD. Note the code below and my comments.

    -- against a variable

    DECLARE @string VARCHAR(256) = 'CN=John Smith,OU=Production,OU=IT,OU=Santa Fe,OU=Region 2,DC=doh,DC=state,DC=nm,DC=us';

    SELECT details = REPLACE(details,'.',' ')

    FROM

    (

    SELECT

    ItemNumber,

    SUBSTRING(Item, 1, CHARINDEX('=',item)-1),

    SUBSTRING(Item, CHARINDEX('=',item)+1,100)

    FROM DelimitedSplit8K_LEAD(@string, ',')

    ) parseAD(itemNumber, container, details)

    WHERE container = 'CN'; -- this filter may need to be updated depending on how the data is stored

    -- against a table

    DECLARE @table TABLE (personID int, managerADInfo varchar(1000));

    INSERT @table

    VALUES

    (1,'CN=John Smith,OU=Production,OU=IT,OU=Santa Fe,OU=Region 2,DC=doh,DC=state,DC=nm,DC=us'),

    (2,'CN=Bill.Jones,OU=Production,OU=IT,OU=Chicago,OU=Region 2,DC=xxx,DC=state,DC=IL,DC=us');

    SELECT

    personID,

    managerADInfo,

    details = REPLACE(details,'.',' ')

    FROM @table

    CROSS APPLY

    (

    SELECT details

    FROM

    (

    SELECT

    ItemNumber,

    SUBSTRING(Item, 1, CHARINDEX('=',item)-1),

    SUBSTRING(Item, CHARINDEX('=',item)+1,100)

    FROM DelimitedSplit8K_LEAD(managerADInfo, ',')

    ) parseAD(itemNumber, container, details)

    WHERE container = 'CN'

    ) parseAD;

    "I cant stress enough the importance of switching from a sequential files mindset to set-based thinking. After you make the switch, you can spend your time tuning and optimizing your queries instead of maintaining lengthy, poor-performing code."

    -- Itzik Ben-Gan 2001

  • Borrowing from Alan's example, the same thing can be done w/o the split function. The split may be faster on huge datasets, but I think just using CROSS APPLY will perform OK for normal processing.

    -- against a table

    DECLARE @table TABLE (personID int, managerADInfo varchar(1000));

    INSERT @table

    VALUES

    (1,'CN=John Smith,OU=Production,OU=IT,OU=Santa Fe,OU=Region 2,DC=doh,DC=state,DC=nm,DC=us'),

    (2,'CN=Bill.Jones,OU=Production,OU=IT,OU=Chicago,OU=Region 2,DC=xxx,DC=state,DC=IL,DC=us'),

    (3,'OU=Production,OU=IT,OU=Chicago,CN=Fred Dudely,OU=Region 2,DC=xxx,DC=state,DC=IL,DC=us');

    SELECT t.*

    , t4.ManagerName

    FROM @table t

    CROSS APPLY (SELECT CHARINDEX('CN=', t.managerADInfo)) t1(CN)

    CROSS APPLY (SELECT t1.CN + 3) t2(NameStartPosition)

    CROSS APPLY (SELECT CHARINDEX(',', t.managerADInfo, t2.NameStartPosition))t3(NameEndPosition)

    CROSS APPLY (SELECT SUBSTRING(t.managerADInfo, t2.NameStartPosition, (t3.NameEndPosition - t2.nameStartPosition)))t4(ManagerName)

    John Rowan

    ======================================================
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  • I also don't see a need to split the entire string in this case, since you all want to extract is the CN= name.

    SELECT

    string,

    CASE WHEN cn_start_byte = 0 THEN ''

    ELSE SUBSTRING(string, cn_start_byte + 3, first_comma_after_cn - cn_start_byte - 3)

    END AS ADManager

    FROM (

    VALUES('CN=John Smith,OU=Production,OU=IT,OU=Santa Fe,OU=Region 2,DC=doh,DC=state,DC=nm,DC=us'),

    ('OU=Production,CN=Jane Seymore,OU=IT,OU=Santa Fe,OU=Region 2,DC=doh,DC=state,DC=nm,DC=us'),

    ('OU=Anywhere,CN=Any name goes here') /* CN= is last entry */

    ) AS test_data(string)

    CROSS APPLY (

    SELECT CHARINDEX('CN=', string) AS cn_start_byte

    ) AS assign_alias_names1

    CROSS APPLY (

    SELECT CHARINDEX(',', string + ',', cn_start_byte + 3) AS first_comma_after_cn

    ) AS assign_alias_names2

    Edit: Added "+ ','" to CA2, which I inadvertently left out of the original code.

    SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".

  • Good answers all, thank you!

    Kindest Regards, Rod Connect with me on LinkedIn.

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