WHERE/HAVING

Definition:

WHERE:Filtering before grouping.

HAVING:Filtering after grouping.

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Command Example:

SELECT CLASS FROM STUDENT
WHERE CLASS_NO IS NULL AND NOT(CLASS = '1A' OR SNAME LIKE '%CHAN_') AND DOB NOT IN('2022-01-31','2014-12-01') OR AGE BETWEEN 12 AND 18
GROUP BY CLASS
HAVING SUM(SCORE1) <= 10 AND AVG(SCORE2) <> MIN(SCORE1) OR MAX(SCORE1) > COUNT(SID);

• Executing order:NOT>AND>OR

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'WHERE is my HAVING hair?'By secondary 6 student