sql修剪并替换

Question

Can i trim and replace at the same time a column's name so i can break it down in two parts? The expected result is in nameL and nameR

name        nameL    nameR
AB_1X       AB       1X
AXG_3X      AXG      3X
4G_12X      4G       12X

Tried using this query:

select *,
RIGHT(name, LEN(name)-4) as nameR,
LEFT(name, LEN(name)-4) as nameL
from myTable

The problem is that it trims like this:

nameL    
AB_
AXG
4G_

same for nameR, because i'm taking a fixed size. How can I eliminate "_" and achieve the expected outcome? Thank you in advance

Answer 1

Try with combination of substring and charindex functions:

DECLARE @t TABLE(name NVARCHAR(10))

INSERT INTO @t VALUES
('AB_1X'),
('AXG_3X'),
('4G_12X')

SELECT name, 
       SUBSTRING(name, 1, CHARINDEX('_', name) - 1) nameL,
       SUBSTRING(name, CHARINDEX('_', name) + 1, LEN(name)) nameR
FROM @t

I assume that there is always underscore symbol in name column.

Answer 2

You can use:

SELECT RIGHT(name, LEN(name) - CHARINDEX('_', name)) AS nameR,
    LEFT(name, CHARINDEX('_', name) - 1) AS nameL
FROM myTable