How to write SQL queries with respect to the following conditions? - sql

Question

I have a database table in which a column tags contain values such as:
"AutoMNRP, MNRP"
"Macro, MNRP"
"AutoMNRP, Micro"
"Macro, Micro"
where "...." represents a string.
I want to write a SQL query such that it filters out all results having MNRP tag in it. How can I do this?
I tried a not like operator of SQL on it, but if I want to remove MNRP tag, it also filters out AutoMNRP tag.
At the last of query I need results featuring -
"AutoMNRP, Micro"
"Macro, Micro".
(Results when MNRP is filtered out.)

Answer 1

The right answer to this is to fix your design, you shouldn't store the data like this (comma separated), because your table should be like (and the duplicates should be removed and handled too)
+----------+
| Data |
+----------+
| AutoMNRP |
| MNRP |
| Macro |
| MNRP |
| AutoMNRP |
| Micro |
| Macro |
| Micro |
+----------+
But... here is a way it may fit you requirements
;WITH T(Str) AS
(
SELECT 'AutoMNRP, MNRP' UNION ALL
SELECT 'Macro, MNRP' UNION ALL
SELECT 'AutoMNRP, Micro' UNION ALL
SELECT 'Macro, Micro'
)
SELECT Str
FROM T
WHERE Str NOT LIKE '% MNRP,%'
AND
Str NOT LIKE '%, MNRP';
Returns:
+-----------------+
| Str |
+-----------------+
| AutoMNRP, Micro |
| Macro, Micro |
+-----------------+
Live Demo
You also (as Larnu point to) do as
;WITH T(Str) AS
(
SELECT 'AutoMNRP, MNRP' UNION ALL
SELECT 'Macro, MNRP' UNION ALL
SELECT 'AutoMNRP, Micro' UNION ALL
SELECT 'Macro, Micro'
)
SELECT Str
FROM T
WHERE CONCAT(', ', Str, ',') NOT LIKE '%, MNRP,';

Answer 2

In SQL Server 2016+ you can use the STRING_SPLIT function. So you can multiply a record by the number of separated values in the tags column so you can then apply a simple WHERE clause. Something like this:
WITH cte AS
(
SELECT Id, SingleTag
FROM table_name CROSS APPLY STRING_SPLIT(tags, ',')
)
SELECT * FROM cte WHERE SingleTag = 'MNRP'