SELECT COUNT(DISTINCT someField) FROM someTable; SELECT DISTINCT someField FROM someTable;
T/F: The value returned by the first will always equal the number of rows returned by the second.
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November 15, 2005
Distinct Count
November 13, 2005
Unique Index
If I run the following, what will happen?
CREATE TABLE myTable (someField int, UNIQUE (someField)); INSERT INTO myTable VALUES (null); INSERT INTO myTable VALUES (NULL);
November 11, 2005
Truncation
Assume the following has completed correctly:
CREATE TABLE test (
charField varchar(5)
);
What is the end difference between the following two statements?
INSERT INTO test (charField) VALUES ("123456");
INSERT INTO test (charField) VALUES ("12345 ");
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November 9, 2005
User Experience
I had a positive user experience at the MySQL website the other day while registering for a webinar. The site knew I was logged in, and filled out as much of the form for me as it could. When I added the missing pieces of information, that next page noticed and provided a single-click where I could add the data to my profile. Added functionality, but completely unobtrusive – that’s the user experience I like.