SQL Server 2012

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CREATE TABLE table_name (
  data VARCHAR(100)
);
INSERT INTO table_name VALUES
  ('test data #item test data #match'),
  ('test data #test');
2 rows affected

SELECT * FROM table_name 
WHERE (DATALENGTH(data) - DATALENGTH(REPLACE(data, '#', ''))) / DATALENGTH('#') >= 2


data


test data #item test data #match


CREATE FUNCTION GetStringCount(@strValue VARCHAR(200), @charValue VARCHAR(200))
RETURNS INT
AS
BEGIN
  RETURN (DATALENGTH(@strValue) - DATALENGTH(REPLACE(@strValue, @charValue, ''))) / DATALENGTH(@charValue)
END
SELECT * FROM table_name WHERE dbo.GetStringCount(data, '#') >= 2


data


test data #item test data #match