Why isnt this SQL command working

SELECT info, date
FROM Professor, Professor_Comment,开发者_运维知识库 Comment
WHERE pID = ?
AND Professor_Comment.pcID = Professor.pcID
AND Comment.commID = Professor_Comment.commID;
;

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That's likely to be because the pID is ambigious and the Professor doesn't have a pcID.

Try this:

SELECT info, date
FROM Professor_Comment, Comment
WHERE pID = ?
AND Comment.commID = Professor_Comment.commID;

However, I prefer the explicit JOIN syntax:

SELECT info, date
FROM Professor_Comment
JOIN Comment ON Comment.commID = Professor_Comment.commID
WHERE pID = ?;

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1. You have pID = ?, but pID is ambiguous because it appears in Professor and Professor_Comment

   Change that sole pID to either Professor.pID or Professor_Comment.pID
   
   

2. You have Professor_Comment.pcID = Professor.pcID, the Professor table has it listed as dID, not pcID