Tutorial :How do I expand comma separated values into separate rows using SQL Server 2005?



Question:

I have a table that looks like this:

ProductId, Color  "1", "red, blue, green"  "2", null  "3", "purple, green"  

And I want to expand it to this:

ProductId, Color  1, red  1, blue  1, green  2, null  3, purple  3, green  

Whats the easiest way to accomplish this? Is it possible without a loop in a proc?


Solution:1

Take a look at this function. I've done similar tricks to split and transpose data in Oracle. Loop over the data inserting the decoded values into a temp table. The convent thing is that MS will let you do this on the fly, while Oracle requires an explicit temp table.

MS SQL Split Function
Better Split Function

Edit by author: This worked great. Final code looked like this (after creating the split function):

select pv.productid, colortable.items as color  from product p       cross apply split(p.color, ',') as colortable  


Solution:2

based on your tables:

create table test_table  (       ProductId  int      ,Color      varchar(100)  )    insert into test_table values (1, 'red, blue, green')  insert into test_table values (2, null)  insert into test_table values (3, 'purple, green')  

create a new table like this:

CREATE TABLE Numbers  (      Number  int   not null primary key  )  

that has rows containing values 1 to 8000 or so.

this will return what you want:

EDIT
here is a much better query, slightly modified from the great answer from @Christopher Klein:

I added the "LTRIM()" so the spaces in the color list, would be handled properly: "red, blue, green". His solution requires no spaces "red,blue,green". Also, I prefer to use my own Number table and not use master.dbo.spt_values, this allows the removal of one derived table too.

SELECT      ProductId, LEFT(PartialColor, CHARINDEX(',', PartialColor + ',')-1) as SplitColor      FROM (SELECT                 t.ProductId, LTRIM(SUBSTRING(t.Color, n.Number, 200)) AS PartialColor                FROM test_table             t                    LEFT OUTER JOIN Numbers n ON n.Number<=LEN(t.Color) AND SUBSTRING(',' + t.Color, n.Number, 1) = ','           ) t  

EDIT END

SELECT      ProductId, Color --,number      FROM (SELECT                ProductId                    ,CASE                         WHEN LEN(List2)>0 THEN LTRIM(RTRIM(SUBSTRING(List2, number+1, CHARINDEX(',', List2, number+1)-number - 1)))                         ELSE NULL                     END AS Color                    ,Number                FROM (                         SELECT ProductId,',' + Color + ',' AS List2                             FROM test_table                     ) AS dt                    LEFT OUTER JOIN Numbers n ON (n.Number < LEN(dt.List2)) OR (n.Number=1 AND dt.List2 IS NULL)                WHERE SUBSTRING(List2, number, 1) = ',' OR List2 IS NULL           ) dt2      ORDER BY ProductId, Number, Color  

here is my result set:

ProductId   Color  ----------- --------------  1           red  1           blue  1           green  2           NULL  3           purple  3           green    (6 row(s) affected)  

which is the same order you want...


Solution:3

You can try this out, doesnt require any additional functions:

  declare @t table (col1 varchar(10), col2 varchar(200))  insert @t            select '1', 'red,blue,green'  union all select '2', NULL  union all select '3', 'green,purple'      select col1, left(d, charindex(',', d + ',')-1) as e from (      select *, substring(col2, number, 200) as d from @t col1 left join          (select distinct number from master.dbo.spt_values where number between 1 and 200) col2          on substring(',' + col2, number, 1) = ',') t  


Solution:4

Fix your database if at all possible. Comma delimited lists in database cells indicate a flawed schema 99% of the time or more.


Solution:5

I would create a CLR table-defined function for this:

http://msdn.microsoft.com/en-us/library/ms254508(VS.80).aspx

The reason for this is that CLR code is going to be much better at parsing apart the strings (computational work) and can pass that information back as a set, which is what SQL Server is really good at (set management).

The CLR function would return a series of records based on the parsed values (and the input id value).

You would then use a CROSS APPLY on each element in your table.


Solution:6

Just convert your columns into xml and query it. Here's an example.

select       a.value('.', 'varchar(42)') c  from (select cast('<r><a>' + replace(@CSV, ',', '</a><a>') + '</a></r>' as xml) x) t1  cross apply x.nodes('//r/a') t2(a)  

Note:If u also have question or solution just comment us below or mail us on toontricks1994@gmail.com
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