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By admin, February 25, 2012 9:58 AM

SELECT
table1.AppointmentDate,
Count(table1.IDfield)
FROM
table1
WHERE
table1.seen = ’1′ AND
table1.AppointmentDate >= ’2007-12-01′ AND
table1.AppointmentDate GROUP BY
table1.AppointmentDate

Comments (0)

By admin, September 5, 2011 8:34 PM

Where the data varies significantly in length from one record to the next with the longest being significantly longer than the average then you need to use a VARCHAR. There is no point in using a CHAR(40) if the average length is only 15 since that will resuult in a lot of wasted space in most records. Using a VARCHAR(40) instead means that you can still fit the leng 40 chharacter values while the average space used will be 15 plus the record length marker overhead.

summary use varchar for variable length fields and use char if you are expecting it to always be the same eg CHAR (ASSS, DASS, FASS, TASS) this is good for a char ie fixed length fields