将一列中的值解析为另一个表中的多列

Question

Microsoft SQL Server 2008

I have two tables. One has a column in it with data that is _ delimited

example:

Y_21_CA
<BR>
such that:
Yes/No_Age_State

I need to parse the data in this column out and insert it into another table that has individual columns for each value. Let's say Table A contains one column like the example above but Table B contains three columns, YesOrNo, Age, usState .

What's the easiest way to do this? I've tried doing something like:

UPDATE TableA
SET YesOrNo = SUBSTRING (TableB.Column1, 1, 1)

but SUBSTRING only takes an expression. I really just need some guidance here, I've been banging my head against the wall trying to figure this out since I'm not much of a SQL guru. I can figure out the syntax no problem but maybe I'm not aware of some methods that exist. Thanks

Answer 1

A generic solution, using Charindex of '_' without hardcoding it

declare @s varchar(10) = 'Y_21_CA'   

SELECT LEFT(@s, CHARINDEX('_',@s,1)-1) YN, 
       SUBSTRING(@s, CHARINDEX('_',@s,1)+1,  
                 CHARINDEX('_',@s,CHARINDEX('_',@s,1)) ) Age,
       RIGHT(@s, CHARINDEX('_',reverse(@s),1)-1) State 

--Results
Y   21   CA

In case you expect to use this logic often in other queries, you could make the SELECT statement an inline TVF. Then you would be able to use it with your update like this:

UPDATE b
SET YesOrNo = x.YN,
    Age = x.Age,
    State = x.State
FROM TableB b
INNER JOIN TableA a ON b.ID = a.ID
CROSS APPLY ThreeColumnSplit(a.S) x;

Here's a "live" demo at SQL Fiddle . (Please never mind its using the SQL Server 2012 engine. That's only because the Fiddle's 2008 instance appears to be down at the moment and can't be used. There's nothing SQL Server 2012-specific in the script.)

Answer 2

You should be able to use the following, I think you want an INSERT instead of UPDATE .

The SELECT statement to get the data is:

select substring(yourCol, 1, 1) YesOrNo,
  substring(yourcol, 3, len(yourcol)-5) Age,
  right(yourCol, 2) usState
from tableA;

See SQL Fiddle with Demo

Then the INSERT statement is:

insert into tableB (YesOrNo, Age, usState)
select substring(yourCol, 1, 1) YesOrNo,
  substring(yourcol, 3, len(yourcol)-5) Age,
  right(yourCol, 2) usState
from tableA;

See SQL Fiddle with Demo

Note: This assumes that the YesOrNo column will always only have one character and that the usState will always have 2 characters.