You column "SequenceNumTxt" either should be a BIGINT or (n)varchar/(n)char to hold this value.
so, if your column data type is BIGINT, try below code
DECLARE @MyTest TABLE
(
SequenceNumTxt BIGINT
)
INSERT INTO @MyTest
VALUES (123412341234), (243), (12312343)
SELECT * FROM @MyTest
WHERE SequenceNumTxt = 123412341234
or if your column data type is (n)varchar/(n)char then try below
DECLARE @MyTestChar TABLE
(
SequenceNumTxt varchar(100)
)
INSERT INTO @MyTestChar
VALUES ('123412341234'), ('243'), ('12312343')
SELECT * FROM @MyTestChar
WHERE SequenceNumTxt = '123412341234'
Let us know if you have other issue than this.