SQL GROUP BY statement can only use number to group?
I am learning SQL now and I am kind of confused when encountering a query like this:
SELECT CASE
WHEN url like '%abc.com%'THEN 'abc'
When url like '%def.com%'THEN 'def'
When url like '%smiley.com%' THEN 'Smiley'
Else 'others'
End AS 'sites', count(*)
FROM websites_sources
GROUP BY 1;
The query above works correctly, but only if the GROUP BY Statement uses 1. If I write Group BY 'sites', the result only shows 'others' and the total count of ALL rows (instead of the count for 'others' only and other sites).
My question is, so for GROUP BY Statement we can only use number to indicate grouping, and not the name of the column?
Thanks for your help!
mysql sql
asked Nov 20 at 2:53
user71812
917
add a comment |
I am learning SQL now and I am kind of confused when encountering a query like this:
SELECT CASE
WHEN url like '%abc.com%'THEN 'abc'
When url like '%def.com%'THEN 'def'
When url like '%smiley.com%' THEN 'Smiley'
Else 'others'
End AS 'sites', count(*)
FROM websites_sources
GROUP BY 1;
The query above works correctly, but only if the GROUP BY Statement uses 1. If I write Group BY 'sites', the result only shows 'others' and the total count of ALL rows (instead of the count for 'others' only and other sites).
My question is, so for GROUP BY Statement we can only use number to indicate grouping, and not the name of the column?
Thanks for your help!
mysql sql
asked Nov 20 at 2:53
user71812
917
add a comment |
I am learning SQL now and I am kind of confused when encountering a query like this:
SELECT CASE
WHEN url like '%abc.com%'THEN 'abc'
When url like '%def.com%'THEN 'def'
When url like '%smiley.com%' THEN 'Smiley'
Else 'others'
End AS 'sites', count(*)
FROM websites_sources
GROUP BY 1;
The query above works correctly, but only if the GROUP BY Statement uses 1. If I write Group BY 'sites', the result only shows 'others' and the total count of ALL rows (instead of the count for 'others' only and other sites).
My question is, so for GROUP BY Statement we can only use number to indicate grouping, and not the name of the column?
Thanks for your help!
mysql sql
asked Nov 20 at 2:53
user71812
917
I am learning SQL now and I am kind of confused when encountering a query like this:
SELECT CASE
WHEN url like '%abc.com%'THEN 'abc'
When url like '%def.com%'THEN 'def'
When url like '%smiley.com%' THEN 'Smiley'
Else 'others'
End AS 'sites', count(*)
FROM websites_sources
GROUP BY 1;
The query above works correctly, but only if the GROUP BY Statement uses 1. If I write Group BY 'sites', the result only shows 'others' and the total count of ALL rows (instead of the count for 'others' only and other sites).
My question is, so for GROUP BY Statement we can only use number to indicate grouping, and not the name of the column?
Thanks for your help!
mysql sql
mysql sql
asked Nov 20 at 2:53
user71812
917
asked Nov 20 at 2:53
user71812
917
asked Nov 20 at 2:53
user71812
917
asked Nov 20 at 2:53
user71812
917
asked Nov 20 at 2:53
user71812
917
917
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Only use single quote for string and date constants. Never use single quotes for column aliases. You'll just confuse yourself.
Try this:
SELECT (CASE WHEN url like '%abc.com%' THEN 'abc'
WHEN url like '%def.com%' THEN 'def'
WHEN url like '%smiley.com%' THEN 'Smiley'
ELSE 'others'
END) AS sites,
count(*)
FROM websites_sources
GROUP BY sites;
You are grouping by the string 'sites', which is a constant, not the column named sites.
answered Nov 20 at 2:55
Gordon Linoff
756k35291399
add a comment |
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1 Answer
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active
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votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Only use single quote for string and date constants. Never use single quotes for column aliases. You'll just confuse yourself.
Try this:
SELECT (CASE WHEN url like '%abc.com%' THEN 'abc'
WHEN url like '%def.com%' THEN 'def'
WHEN url like '%smiley.com%' THEN 'Smiley'
ELSE 'others'
END) AS sites,
count(*)
FROM websites_sources
GROUP BY sites;
You are grouping by the string 'sites', which is a constant, not the column named sites.
answered Nov 20 at 2:55
Gordon Linoff
756k35291399
add a comment |
Only use single quote for string and date constants. Never use single quotes for column aliases. You'll just confuse yourself.
Try this:
SELECT (CASE WHEN url like '%abc.com%' THEN 'abc'
WHEN url like '%def.com%' THEN 'def'
WHEN url like '%smiley.com%' THEN 'Smiley'
ELSE 'others'
END) AS sites,
count(*)
FROM websites_sources
GROUP BY sites;
You are grouping by the string 'sites', which is a constant, not the column named sites.
answered Nov 20 at 2:55
Gordon Linoff
756k35291399
add a comment |
Only use single quote for string and date constants. Never use single quotes for column aliases. You'll just confuse yourself.
Try this:
SELECT (CASE WHEN url like '%abc.com%' THEN 'abc'
WHEN url like '%def.com%' THEN 'def'
WHEN url like '%smiley.com%' THEN 'Smiley'
ELSE 'others'
END) AS sites,
count(*)
FROM websites_sources
GROUP BY sites;
You are grouping by the string 'sites', which is a constant, not the column named sites.
answered Nov 20 at 2:55
Gordon Linoff
756k35291399
Only use single quote for string and date constants. Never use single quotes for column aliases. You'll just confuse yourself.
Try this:
SELECT (CASE WHEN url like '%abc.com%' THEN 'abc'
WHEN url like '%def.com%' THEN 'def'
WHEN url like '%smiley.com%' THEN 'Smiley'
ELSE 'others'
END) AS sites,
count(*)
FROM websites_sources
GROUP BY sites;
You are grouping by the string 'sites', which is a constant, not the column named sites.
answered Nov 20 at 2:55
Gordon Linoff
756k35291399
answered Nov 20 at 2:55
Gordon Linoff
756k35291399
answered Nov 20 at 2:55
Gordon Linoff
756k35291399
answered Nov 20 at 2:55
Gordon Linoff
756k35291399
756k35291399
add a comment |
add a comment |
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