Postgresql Compare varchar and time type
up vote
0
down vote
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In PostgreSQL, I need to make a LEFT JOIN between two columns that are different in data type. One of them is varchar and the other is time
LEFT JOIN my_table ON r.varchar_time = my_table.time
How can I compare them, by using to_char?
sql postgresql
asked Nov 19 at 22:40
pmirnd
68521129
add a comment |
up vote
0
down vote
favorite
In PostgreSQL, I need to make a LEFT JOIN between two columns that are different in data type. One of them is varchar and the other is time
LEFT JOIN my_table ON r.varchar_time = my_table.time
How can I compare them, by using to_char?
sql postgresql
asked Nov 19 at 22:40
pmirnd
68521129
You really ought to provide some sample data with this question, or we have to guess what it looks like.
– Used_By_Already
Nov 19 at 23:54
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
In PostgreSQL, I need to make a LEFT JOIN between two columns that are different in data type. One of them is varchar and the other is time
LEFT JOIN my_table ON r.varchar_time = my_table.time
How can I compare them, by using to_char?
sql postgresql
asked Nov 19 at 22:40
pmirnd
68521129
In PostgreSQL, I need to make a LEFT JOIN between two columns that are different in data type. One of them is varchar and the other is time
LEFT JOIN my_table ON r.varchar_time = my_table.time
How can I compare them, by using to_char?
sql postgresql
sql postgresql
asked Nov 19 at 22:40
pmirnd
68521129
asked Nov 19 at 22:40
pmirnd
68521129
asked Nov 19 at 22:40
pmirnd
68521129
asked Nov 19 at 22:40
pmirnd
68521129
asked Nov 19 at 22:40
pmirnd
68521129
68521129
You really ought to provide some sample data with this question, or we have to guess what it looks like.
– Used_By_Already
Nov 19 at 23:54
add a comment |
You really ought to provide some sample data with this question, or we have to guess what it looks like.
– Used_By_Already
Nov 19 at 23:54
You really ought to provide some sample data with this question, or we have to guess what it looks like.
– Used_By_Already
Nov 19 at 23:54
You really ought to provide some sample data with this question, or we have to guess what it looks like.
– Used_By_Already
Nov 19 at 23:54
add a comment |
2 Answers
2
active
oldest
votes
up vote
1
down vote
accepted
Type conversions may use an abbreviated syntax such as ::time so, you may be able to use:
LEFT JOIN my_table ON r.varchar_time::time = my_table.time
However if there are any values that don't convert to time that may error. You might go in the opposite direction, but now you must ensure that the format produced by the varchar conversion matches the other column's format.
LEFT JOIN my_table ON r.varchar_time = my_table.time::varchar
Either way you have potential problems. Ideally that varchar column would be time as well.
The other possible issue I see with this is that time precision might be a problem as well, but this depends on how you populate the columns.
test:
select
(current_timestamp::time)::varchar "varchar"
, current_timestamp::time "time"
+-----------------+------------------+
| varchar | time |
+-----------------+------------------+
| 00:50:20.703713 | 00:50:20.7037130 |
+-----------------+------------------+
As you can see from this test the "format" of your varchar data will matter
answered Nov 19 at 23:46
Used_By_Already
22.2k21838
This one works, I have no error but the result of what I'm selecting is empty, but that has to be a problem with my joins. In the end, I had to use this:LEFT JOIN my_table ON extract(hour from r.varchar_time::time) = extract(hour from my_table.time)
– pmirnd
Nov 20 at 18:28
This was the answer that helped me most. Thanks.
– pmirnd
Nov 20 at 19:11
add a comment |
up vote
1
down vote
Postgres has functions to convert from one datatype to another. From the docs:
to_timestamp(text, text) , timestamp with time zone, converts string to time stamp
Example: to_timestamp('05 Dec 2000', 'DD Mon YYYY')
Your code might look like this, using whichever format you need to match the other column.
LEFT JOIN my_table ON to_timestamp(r.varchar_time, 'HH:mm:ss') = my_table.time
answered Nov 19 at 22:46
Adrian J. Moreno
10k12634
I got this: [Err] ERROR: operator doesn't exists: timestamp with time zone = time without time zone
– pmirnd
Nov 19 at 22:50
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
up vote
1
down vote
accepted
Type conversions may use an abbreviated syntax such as ::time so, you may be able to use:
LEFT JOIN my_table ON r.varchar_time::time = my_table.time
However if there are any values that don't convert to time that may error. You might go in the opposite direction, but now you must ensure that the format produced by the varchar conversion matches the other column's format.
LEFT JOIN my_table ON r.varchar_time = my_table.time::varchar
Either way you have potential problems. Ideally that varchar column would be time as well.
The other possible issue I see with this is that time precision might be a problem as well, but this depends on how you populate the columns.
test:
select
(current_timestamp::time)::varchar "varchar"
, current_timestamp::time "time"
+-----------------+------------------+
| varchar | time |
+-----------------+------------------+
| 00:50:20.703713 | 00:50:20.7037130 |
+-----------------+------------------+
As you can see from this test the "format" of your varchar data will matter
answered Nov 19 at 23:46
Used_By_Already
22.2k21838
This one works, I have no error but the result of what I'm selecting is empty, but that has to be a problem with my joins. In the end, I had to use this:LEFT JOIN my_table ON extract(hour from r.varchar_time::time) = extract(hour from my_table.time)
– pmirnd
Nov 20 at 18:28
This was the answer that helped me most. Thanks.
– pmirnd
Nov 20 at 19:11
add a comment |
up vote
1
down vote
accepted
Type conversions may use an abbreviated syntax such as ::time so, you may be able to use:
LEFT JOIN my_table ON r.varchar_time::time = my_table.time
However if there are any values that don't convert to time that may error. You might go in the opposite direction, but now you must ensure that the format produced by the varchar conversion matches the other column's format.
LEFT JOIN my_table ON r.varchar_time = my_table.time::varchar
Either way you have potential problems. Ideally that varchar column would be time as well.
The other possible issue I see with this is that time precision might be a problem as well, but this depends on how you populate the columns.
test:
select
(current_timestamp::time)::varchar "varchar"
, current_timestamp::time "time"
+-----------------+------------------+
| varchar | time |
+-----------------+------------------+
| 00:50:20.703713 | 00:50:20.7037130 |
+-----------------+------------------+
As you can see from this test the "format" of your varchar data will matter
answered Nov 19 at 23:46
Used_By_Already
22.2k21838
This one works, I have no error but the result of what I'm selecting is empty, but that has to be a problem with my joins. In the end, I had to use this:LEFT JOIN my_table ON extract(hour from r.varchar_time::time) = extract(hour from my_table.time)
– pmirnd
Nov 20 at 18:28
This was the answer that helped me most. Thanks.
– pmirnd
Nov 20 at 19:11
add a comment |
up vote
1
down vote
accepted
up vote
1
down vote
accepted
Type conversions may use an abbreviated syntax such as ::time so, you may be able to use:
LEFT JOIN my_table ON r.varchar_time::time = my_table.time
However if there are any values that don't convert to time that may error. You might go in the opposite direction, but now you must ensure that the format produced by the varchar conversion matches the other column's format.
LEFT JOIN my_table ON r.varchar_time = my_table.time::varchar
Either way you have potential problems. Ideally that varchar column would be time as well.
The other possible issue I see with this is that time precision might be a problem as well, but this depends on how you populate the columns.
test:
select
(current_timestamp::time)::varchar "varchar"
, current_timestamp::time "time"
+-----------------+------------------+
| varchar | time |
+-----------------+------------------+
| 00:50:20.703713 | 00:50:20.7037130 |
+-----------------+------------------+
As you can see from this test the "format" of your varchar data will matter
answered Nov 19 at 23:46
Used_By_Already
22.2k21838
Type conversions may use an abbreviated syntax such as ::time so, you may be able to use:
LEFT JOIN my_table ON r.varchar_time::time = my_table.time
However if there are any values that don't convert to time that may error. You might go in the opposite direction, but now you must ensure that the format produced by the varchar conversion matches the other column's format.
LEFT JOIN my_table ON r.varchar_time = my_table.time::varchar
Either way you have potential problems. Ideally that varchar column would be time as well.
The other possible issue I see with this is that time precision might be a problem as well, but this depends on how you populate the columns.
test:
select
(current_timestamp::time)::varchar "varchar"
, current_timestamp::time "time"
+-----------------+------------------+
| varchar | time |
+-----------------+------------------+
| 00:50:20.703713 | 00:50:20.7037130 |
+-----------------+------------------+
As you can see from this test the "format" of your varchar data will matter
answered Nov 19 at 23:46
Used_By_Already
22.2k21838
edited Nov 19 at 23:53
answered Nov 19 at 23:46
Used_By_Already
22.2k21838
answered Nov 19 at 23:46
Used_By_Already
22.2k21838
answered Nov 19 at 23:46
Used_By_Already
22.2k21838
22.2k21838
This one works, I have no error but the result of what I'm selecting is empty, but that has to be a problem with my joins. In the end, I had to use this:LEFT JOIN my_table ON extract(hour from r.varchar_time::time) = extract(hour from my_table.time)
– pmirnd
Nov 20 at 18:28
This was the answer that helped me most. Thanks.
– pmirnd
Nov 20 at 19:11
add a comment |
This one works, I have no error but the result of what I'm selecting is empty, but that has to be a problem with my joins. In the end, I had to use this:LEFT JOIN my_table ON extract(hour from r.varchar_time::time) = extract(hour from my_table.time)
– pmirnd
Nov 20 at 18:28
This was the answer that helped me most. Thanks.
– pmirnd
Nov 20 at 19:11
This one works, I have no error but the result of what I'm selecting is empty, but that has to be a problem with my joins. In the end, I had to use this:
LEFT JOIN my_table ON extract(hour from r.varchar_time::time) = extract(hour from my_table.time)– pmirnd
Nov 20 at 18:28
This one works, I have no error but the result of what I'm selecting is empty, but that has to be a problem with my joins. In the end, I had to use this:
LEFT JOIN my_table ON extract(hour from r.varchar_time::time) = extract(hour from my_table.time)– pmirnd
Nov 20 at 18:28
This was the answer that helped me most. Thanks.
– pmirnd
Nov 20 at 19:11
This was the answer that helped me most. Thanks.
– pmirnd
Nov 20 at 19:11
add a comment |
up vote
1
down vote
Postgres has functions to convert from one datatype to another. From the docs:
to_timestamp(text, text) , timestamp with time zone, converts string to time stamp
Example: to_timestamp('05 Dec 2000', 'DD Mon YYYY')
Your code might look like this, using whichever format you need to match the other column.
LEFT JOIN my_table ON to_timestamp(r.varchar_time, 'HH:mm:ss') = my_table.time
answered Nov 19 at 22:46
Adrian J. Moreno
10k12634
I got this: [Err] ERROR: operator doesn't exists: timestamp with time zone = time without time zone
– pmirnd
Nov 19 at 22:50
add a comment |
up vote
1
down vote
Postgres has functions to convert from one datatype to another. From the docs:
to_timestamp(text, text) , timestamp with time zone, converts string to time stamp
Example: to_timestamp('05 Dec 2000', 'DD Mon YYYY')
Your code might look like this, using whichever format you need to match the other column.
LEFT JOIN my_table ON to_timestamp(r.varchar_time, 'HH:mm:ss') = my_table.time
answered Nov 19 at 22:46
Adrian J. Moreno
10k12634
I got this: [Err] ERROR: operator doesn't exists: timestamp with time zone = time without time zone
– pmirnd
Nov 19 at 22:50
add a comment |
up vote
1
down vote
up vote
1
down vote
Postgres has functions to convert from one datatype to another. From the docs:
to_timestamp(text, text) , timestamp with time zone, converts string to time stamp
Example: to_timestamp('05 Dec 2000', 'DD Mon YYYY')
Your code might look like this, using whichever format you need to match the other column.
LEFT JOIN my_table ON to_timestamp(r.varchar_time, 'HH:mm:ss') = my_table.time
answered Nov 19 at 22:46
Adrian J. Moreno
10k12634
Postgres has functions to convert from one datatype to another. From the docs:
to_timestamp(text, text) , timestamp with time zone, converts string to time stamp
Example: to_timestamp('05 Dec 2000', 'DD Mon YYYY')
Your code might look like this, using whichever format you need to match the other column.
LEFT JOIN my_table ON to_timestamp(r.varchar_time, 'HH:mm:ss') = my_table.time
answered Nov 19 at 22:46
Adrian J. Moreno
10k12634
answered Nov 19 at 22:46
Adrian J. Moreno
10k12634
answered Nov 19 at 22:46
Adrian J. Moreno
10k12634
answered Nov 19 at 22:46
Adrian J. Moreno
10k12634
10k12634
I got this: [Err] ERROR: operator doesn't exists: timestamp with time zone = time without time zone
– pmirnd
Nov 19 at 22:50
add a comment |
I got this: [Err] ERROR: operator doesn't exists: timestamp with time zone = time without time zone
– pmirnd
Nov 19 at 22:50
I got this: [Err] ERROR: operator doesn't exists: timestamp with time zone = time without time zone
– pmirnd
Nov 19 at 22:50
I got this: [Err] ERROR: operator doesn't exists: timestamp with time zone = time without time zone
– pmirnd
Nov 19 at 22:50
add a comment |
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You really ought to provide some sample data with this question, or we have to guess what it looks like.
– Used_By_Already
Nov 19 at 23:54