Use SUBSTRING AND CHARINDEX to get last complete word in field - tsql

Question

I have a field in my database that I plan to truncate, for reporting purposes, to 50 characters with the statement below.
SELECT (CASE WHEN (LEN(Notes) > 50) THEN SUBSTRING(Notes, 0, 50) + '...' WHEN (LEN(Notes) < 50) THEN SUBSTRING(Notes, 0, LEN(Notes)) + '...' ELSE 'NO NOTES WERE ENTERED' END) AS Notes FROM MyTable
This works great, however, I would like to complete the last word in the notes field so that a word isn't cut off so I would like to use CHARINDEX, SUBSTRING, REVERSE and possibly the RIGHT function to return the last complete word that is part of a string roughly 50 characters long.
I have experimented and I'm not having much luck.
Any help would be appreciated.

Answer 1

If the length of your notes column is over 50, you can use CHARINDEX to find the next space after position 50 and SUBSTRING to that position. Here is a SQL Fiddle.
SELECT RTRIM(
CASE
-- when the length is less than 50, or the character at position 50 is part of the last word, return the entire string
WHEN LEN(notes) < 50 OR (SUBSTRING(notes,50,1) <> ' ' AND CHARINDEX(' ',notes,50) = 0)
THEN notes
-- when the character at position 50 is a space, return the first 50 characters of the string
WHEN SUBSTRING(notes,50,1) = ' '
THEN LEFT(notes, 50)
-- when the character at position 50 is a word, cut off the string at the next space after 50
WHEN SUBSTRING(notes,50,1) <> ' '
THEN LEFT(notes,CHARINDEX(' ',notes,50))
END) AS first_50
FROM tbl_notes

Answer 2

In case you don't want to exceed the character limit you could have it like this:
DECLARE #Table TABLE
(
String nvarchar(100)
)
DECLARE
#Size int = 25
INSERT #Table SELECT 'Lorem ipsum dolor sit ame'
INSERT #Table SELECT 'Lorem ipsum dolor sit ame tas'
INSERT #Table SELECT 'Lorem ipsum dolor sit am asd'
INSERT #Table SELECT 'Lorem ipsum dolor sita am'
INSERT #Table SELECT 'Lorem ipsum dolor sita a amet, consectetur adipiscing elit,'
INSERT #Table SELECT 'Lorem ipsum dolor sita'
INSERT #Table SELECT 'Lorem ipsum dolor sita asamet, consectetur adipiscing elit,'
SELECT
LEN(R.LimitTruncation) AS LimitTruncationLen,
R.LimitTruncation,
LEN(String) AS StringLen,
R.String
FROM
(
SELECT
String,
--This is the main part
CASE
WHEN LEN(String) <= #Size THEN String
WHEN CHARINDEX(' ', String, #Size) = #Size OR CHARINDEX(' ', String, #Size) = #Size + 1 THEN RTRIM(LEFT(String, #Size))
ELSE REVERSE(SUBSTRING(REVERSE(LEFT(String, #Size)), CHARINDEX(' ', REVERSE(LEFT(String, #Size))), #Size))
END AS LimitTruncation
FROM
#Table
) R