Select unique values of 3 columns from a sql table which has 7 columns
This is what my table looks like.
I want to get unique 'sets' of origin, destination, and flight_date.
So, for the table shown, my query should return {['BLR','DEL', '2019-01-10'], ['BLR','DEL', '2019-01-11']}
javascript mysql node.js
asked Jan 8 at 12:55
Khadar111Khadar111
146
add a comment |
This is what my table looks like.
I want to get unique 'sets' of origin, destination, and flight_date.
So, for the table shown, my query should return {['BLR','DEL', '2019-01-10'], ['BLR','DEL', '2019-01-11']}
javascript mysql node.js
asked Jan 8 at 12:55
Khadar111Khadar111
146
add a comment |
This is what my table looks like.
I want to get unique 'sets' of origin, destination, and flight_date.
So, for the table shown, my query should return {['BLR','DEL', '2019-01-10'], ['BLR','DEL', '2019-01-11']}
javascript mysql node.js
asked Jan 8 at 12:55
Khadar111Khadar111
146
This is what my table looks like.
I want to get unique 'sets' of origin, destination, and flight_date.
So, for the table shown, my query should return {['BLR','DEL', '2019-01-10'], ['BLR','DEL', '2019-01-11']}
javascript mysql node.js
javascript mysql node.js
asked Jan 8 at 12:55
Khadar111Khadar111
146
asked Jan 8 at 12:55
Khadar111Khadar111
146
edited 4 hours ago
Khadar111
asked Jan 8 at 12:55
Khadar111Khadar111
146
asked Jan 8 at 12:55
Khadar111Khadar111
146
asked Jan 8 at 12:55
Khadar111Khadar111
146
146
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
In MySQL this should do the trick:
SELECT DISTINCT origin, destination, flight_date FROM flights
Alternatively:
SELECT origin, destination, flight_date
FROM flights
GROUP BY origin, destination, flight_date
DISTINCT basically means "Make sure the rows are unique", wheras the advantage of using GROUP BY is, that you can use aggregate functions with it (summing, average etc). Also you can add additional conditions using HAVING.
Example:
SELECT origin, destination, flight_date, SUM(time_bucket) AS time_bucket_total
FROM flights
GROUP BY origin, destination, flight_date
HAVING SUM(time_bucket) > 3
This will return the summed time_bucket values along each row, and will also return only those entries where that sum is greater than 3.
answered Jan 8 at 12:59
Markus KleinMarkus Klein
112
It works! is either of the above more efficient than the other?
– Khadar111
Jan 8 at 13:07
@Khadar111 the performance difference is trivial between the two. I like the top one personally, but the second one potentially provides more flexiblity
– NappingRabbit
Jan 8 at 13:13
@NappingRabbit Can you elaborate on how the second one provides more flexibility?
– Khadar111
Jan 8 at 13:26
@Khadar111, I've edited and elaborated the post.
– Markus Klein
yesterday
add a comment |
Add group by the columns you want to select unique values of
answered Jan 8 at 13:03
BoscoBosco
294
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
In MySQL this should do the trick:
SELECT DISTINCT origin, destination, flight_date FROM flights
Alternatively:
SELECT origin, destination, flight_date
FROM flights
GROUP BY origin, destination, flight_date
DISTINCT basically means "Make sure the rows are unique", wheras the advantage of using GROUP BY is, that you can use aggregate functions with it (summing, average etc). Also you can add additional conditions using HAVING.
Example:
SELECT origin, destination, flight_date, SUM(time_bucket) AS time_bucket_total
FROM flights
GROUP BY origin, destination, flight_date
HAVING SUM(time_bucket) > 3
This will return the summed time_bucket values along each row, and will also return only those entries where that sum is greater than 3.
answered Jan 8 at 12:59
Markus KleinMarkus Klein
112
It works! is either of the above more efficient than the other?
– Khadar111
Jan 8 at 13:07
@Khadar111 the performance difference is trivial between the two. I like the top one personally, but the second one potentially provides more flexiblity
– NappingRabbit
Jan 8 at 13:13
@NappingRabbit Can you elaborate on how the second one provides more flexibility?
– Khadar111
Jan 8 at 13:26
@Khadar111, I've edited and elaborated the post.
– Markus Klein
yesterday
add a comment |
In MySQL this should do the trick:
SELECT DISTINCT origin, destination, flight_date FROM flights
Alternatively:
SELECT origin, destination, flight_date
FROM flights
GROUP BY origin, destination, flight_date
DISTINCT basically means "Make sure the rows are unique", wheras the advantage of using GROUP BY is, that you can use aggregate functions with it (summing, average etc). Also you can add additional conditions using HAVING.
Example:
SELECT origin, destination, flight_date, SUM(time_bucket) AS time_bucket_total
FROM flights
GROUP BY origin, destination, flight_date
HAVING SUM(time_bucket) > 3
This will return the summed time_bucket values along each row, and will also return only those entries where that sum is greater than 3.
answered Jan 8 at 12:59
Markus KleinMarkus Klein
112
It works! is either of the above more efficient than the other?
– Khadar111
Jan 8 at 13:07
@Khadar111 the performance difference is trivial between the two. I like the top one personally, but the second one potentially provides more flexiblity
– NappingRabbit
Jan 8 at 13:13
@NappingRabbit Can you elaborate on how the second one provides more flexibility?
– Khadar111
Jan 8 at 13:26
@Khadar111, I've edited and elaborated the post.
– Markus Klein
yesterday
add a comment |
In MySQL this should do the trick:
SELECT DISTINCT origin, destination, flight_date FROM flights
Alternatively:
SELECT origin, destination, flight_date
FROM flights
GROUP BY origin, destination, flight_date
DISTINCT basically means "Make sure the rows are unique", wheras the advantage of using GROUP BY is, that you can use aggregate functions with it (summing, average etc). Also you can add additional conditions using HAVING.
Example:
SELECT origin, destination, flight_date, SUM(time_bucket) AS time_bucket_total
FROM flights
GROUP BY origin, destination, flight_date
HAVING SUM(time_bucket) > 3
This will return the summed time_bucket values along each row, and will also return only those entries where that sum is greater than 3.
answered Jan 8 at 12:59
Markus KleinMarkus Klein
112
In MySQL this should do the trick:
SELECT DISTINCT origin, destination, flight_date FROM flights
Alternatively:
SELECT origin, destination, flight_date
FROM flights
GROUP BY origin, destination, flight_date
DISTINCT basically means "Make sure the rows are unique", wheras the advantage of using GROUP BY is, that you can use aggregate functions with it (summing, average etc). Also you can add additional conditions using HAVING.
Example:
SELECT origin, destination, flight_date, SUM(time_bucket) AS time_bucket_total
FROM flights
GROUP BY origin, destination, flight_date
HAVING SUM(time_bucket) > 3
This will return the summed time_bucket values along each row, and will also return only those entries where that sum is greater than 3.
answered Jan 8 at 12:59
Markus KleinMarkus Klein
112
edited yesterday
answered Jan 8 at 12:59
Markus KleinMarkus Klein
112
answered Jan 8 at 12:59
Markus KleinMarkus Klein
112
answered Jan 8 at 12:59
Markus KleinMarkus Klein
112
112
It works! is either of the above more efficient than the other?
– Khadar111
Jan 8 at 13:07
@Khadar111 the performance difference is trivial between the two. I like the top one personally, but the second one potentially provides more flexiblity
– NappingRabbit
Jan 8 at 13:13
@NappingRabbit Can you elaborate on how the second one provides more flexibility?
– Khadar111
Jan 8 at 13:26
@Khadar111, I've edited and elaborated the post.
– Markus Klein
yesterday
add a comment |
It works! is either of the above more efficient than the other?
– Khadar111
Jan 8 at 13:07
@Khadar111 the performance difference is trivial between the two. I like the top one personally, but the second one potentially provides more flexiblity
– NappingRabbit
Jan 8 at 13:13
@NappingRabbit Can you elaborate on how the second one provides more flexibility?
– Khadar111
Jan 8 at 13:26
@Khadar111, I've edited and elaborated the post.
– Markus Klein
yesterday
It works! is either of the above more efficient than the other?
– Khadar111
Jan 8 at 13:07
It works! is either of the above more efficient than the other?
– Khadar111
Jan 8 at 13:07
@Khadar111 the performance difference is trivial between the two. I like the top one personally, but the second one potentially provides more flexiblity
– NappingRabbit
Jan 8 at 13:13
@Khadar111 the performance difference is trivial between the two. I like the top one personally, but the second one potentially provides more flexiblity
– NappingRabbit
Jan 8 at 13:13
@NappingRabbit Can you elaborate on how the second one provides more flexibility?
– Khadar111
Jan 8 at 13:26
@NappingRabbit Can you elaborate on how the second one provides more flexibility?
– Khadar111
Jan 8 at 13:26
@Khadar111, I've edited and elaborated the post.
– Markus Klein
yesterday
@Khadar111, I've edited and elaborated the post.
– Markus Klein
yesterday
add a comment |
Add group by the columns you want to select unique values of
answered Jan 8 at 13:03
BoscoBosco
294
add a comment |
Add group by the columns you want to select unique values of
answered Jan 8 at 13:03
BoscoBosco
294
add a comment |
Add group by the columns you want to select unique values of
answered Jan 8 at 13:03
BoscoBosco
294
Add group by the columns you want to select unique values of
answered Jan 8 at 13:03
BoscoBosco
294
answered Jan 8 at 13:03
BoscoBosco
294
answered Jan 8 at 13:03
BoscoBosco
294
answered Jan 8 at 13:03
BoscoBosco
294
294
add a comment |
add a comment |
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