T-SQL Procedure not working, issue with varchar to date conversion - sql

Question

When I run this SP, I get:
Msg 241, Level 16, State 1, Procedure PED_SP_PED_Updates, Line 22
Conversion failed when converting date and/or time from character string.
Here is the execution:
exec dbo.ped_sp_ped_updates
#CURRENTHICN='111111111A',
#DATERECEIVED = '20140904',
#FIELDTOBECHANGED='FIRST_NAME_MEMBER',
#CURRENTFIELDVALUE = 'MARY',
#NEWFIELDVALUE = 'MARYTEST',
#REQUESTEDBY = 'IPISORS',
#ID=156
I am not sure why, I'm casting the varchar back to a date for the comparison.
Please note, I have no problem being told a better way to do it, but it would be (I think) more helpful to my learning if I could, at least 'also', get a direct answer as to why my current proc isn't working. In addition to any helpful ideas as to why it should be done different, better, etc, etc. etc.
ALTER PROCEDURE [dbo].[PED_SP_PED_Updates]
#CurrentHicn VARCHAR(500),
#DateReceived VARCHAR(20),
#FieldToBeChanged VARCHAR(500),
#CurrentFieldValue VARCHAR(500),
#NewFieldValue VARCHAR (500),
#RequestedBy VARCHAR(10),
#ID int
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
-- Insert statements for procedure here
DECLARE #CurrentDBNote VARCHAR(MAX)
DECLARE #NewNote VARCHAR(MAX)
DECLARE #CountofHicn INT
SET #NEWNOTE = 'Isaac Pisors | ' + GetDate() + ' | '
+ 'Changing field: ' + #FieldToBeChanged + ' from ' + #CurrentFieldValue + ' to ' + #NewFieldValue
+ ', per ' + #RequestedBy + ' request. Also changing any related DOCS/FAXES records to correspond'
SET #CurrentDBNote=
(SELECT NOTES_GENERAL FROM PED_APPLICATIONS WHERE HICN_MEDICARE_NUMBER=#CurrentHicn AND (Cast(ISNULL(DATE_RECEIVED,'1900-01-01') as DATE)=CAST(#DateReceived AS DATE)))
--NOW ADD THE TWO:
SET #NewNote = #CurrentDBNote + CHAR(13) + #CurrentDBNote
--SEE IF THERE IS STILL A MATCHING RECORD
SET #CountofHicn=
(SELECT COUNT(*) FROM PED_APPLICATIONS WHERE HICN_MEDICARE_NUMBER=#CurrentHicn AND (CAST(ISNULL(DATE_RECEIVED,'1900-01-01') AS DATE)=CAST(#DateReceived AS DATE)))
IF #CountofHicn=0 --THERE IS NO LONGER A MATCHING RECORD - INSERT THAT NOTE AND CALL IT A DAY
BEGIN
UPDATE PED_PEDUPDATES SET COMPLETEDON=GetDate(), COMPLETEDBY='SSIS',
EXCEPTIONNOTE='Could not locate any records where HICN is ' + #CurrentHicn + ' and Date Received is ' + CAST(#DateReceived AS VARCHAR)
WHERE [ID]=#ID
END
ELSE --GO AHEAD AND DO THE UPDATE
BEGIN
UPDATE PED_APPLICATIONS SET #FieldToBeChanged = #NewFieldValue
WHERE HICN_MEDICARE_NUMBER=#CurrentHicn AND (CAST(ISNULL(DATE_RECEIVED,'1900-01-01') AS DATE)=CAST(#DateReceived AS DATE))
END
IF #FieldToBeChanged='HICN_MEDICARE_NUMBER' --THEN WE HAVE TO UPDATE DOCS TABLE, TOO
BEGIN
UPDATE PED_DOCS SET HICN_MEDICARE_NUMBER=#NewFieldValue
WHERE
(HICN_MEDICARE_NUMBER=#CurrentFieldValue AND (CAST(ISNULL(DATE_RECEIVED,'1900-01-01') AS DATE)=#DateReceived)) or
(HICN_MEDICARE_NUMBER=#CurrentFieldValue AND DATE_RECEIVED IS NULL)
END
IF #FieldToBeChanged='HICN_MEDICARE_NUMBER' --THEN OUR WHERE CLAUSE-HICN IS THE *NEW* HICN
BEGIN
UPDATE PED_APPLICATIONS SET NOTES_GENERAL=#NewNote
WHERE HICN_MEDICARE_NUMBER=#NewFieldValue AND (CAST(ISNULL(DATE_RECEIVED,'1900-01-01') AS DATE)=CAST(#DateReceived AS DATE))
END
ELSE --ELSE OUR WHERE CLAUSE-HICN IS THE *OLD* HICN
BEGIN
UPDATE PED_APPLICATIONS SET NOTES_GENERAL=#NewNote
WHERE HICN_MEDICARE_NUMBER=#CurrentHicn AND (CAST(ISNULL(DATE_RECEIVED,'1900-01-01') AS DATE)=CAST(#DateReceived AS DATE))
END
--FINALLY, UPDATE RECORD AS COMPLETE:
UPDATE PED_PEDUPDATES SET COMPLETEDON=GetDate(),COMPLETEDBY='SSIS' WHERE [ID]=#ID
END
GO

Answer 1

Short Term Fix
Instead of CAST(#DateReceived AS DATE), use CONVERT(date, #DateReceived, 112)
The value 112 is the style code for the yyyymmdd formated varchar you're using. See the cast and convert documentation for more details.
Also, you should verify that all values in the DATE_RECEIVED column of your table are in the correct format. Even one value that is not convertible will cause this error.
Proper Fix
#DateReceived should be passed in to the procedure as a date instead of a varchar.
The DATE_RECEIVED field in your table should be declared as a date instead of a varchar.
In general, avoid treating dates or times as strings in a database when there are native types for that purpose.