I have a text column in PostgreSQL that I am ordering by in ASC order and it is returning the following order:
SELECT column_A FROM table ORDER BY column_A ASC:
column_A
IKvap06:52:22.52
i.lost.all.my.tacos
IQKPb06:55:51.53
But I was expecting this:
column_A
i.lost.all.my.tacos
IKvap06:52:22.52
IQKPb06:55:51.53
Any ideas as to why/how this happening? Using locale: en_US.UTF8
I double checked the locale in the database instance to make sure it was en_US.UTF8. I can't seem figure out why I am getting this sort.
Related
I have a table with a few key columns created with nvarchar(80) => unicode.
I can list the full dataset with SELECT * statement (Table1) and can confirm the values I need to filter are there.
However, I can't get any results from that table if I filter rows by using as input an alphabet char on any column.
Columns in table1 stores values in cyrilic characters.
I know it must have to do with character encoding => what I see in the result list is not what I use as input characters.
Unicode nvarchar type should resolve automatically this character type mismatch.
What do you suggest me to do in order to get results?
Thank you very much.
Paulo
a is value entered by user.
cur.execute('SELECT * FROM table WHERE Column-name LIKE ?', ('%{}%'.format(a,))
The database must show value matching with entered value. It shows for one column only. I want to retrieve record for more than one column. Need to use OR operator but not sure the syntax. Could anyone plz help me.
Just expand the where clause with more conditions, separated by OR - accordingly, you need to repeat the bind parameters:
cur.execute('SELECT * FROM table WHERE col1 LIKE ? OR col2 LIKE ?', ('%{}%'.format(a, a))
I see an issue in Cassandra boolean datatype,
I have a table with one field as boolean
CREATE TABLE keyspace.issuetable (
"partitionId" text,
"name" text,
"field" text,
"testboolean" boolean,
PRIMARY KEY ("partitionId", "name"));
Now when I try to insert in table, I didn't add the boolean 'testboolean'
INSERT into keyspace.issuetable("partitionId", "name", "field")
VALUES ('testpartition', 'cluster1_name','testfiled');
Issue :
1) If the boolean entry (say testboolean entry) in INSERT query is not added so as per the data type it needs to be 'false' but it is added as null
SELECT * FROM issuetable ;
partitionId | name | field | testboolean
---------------+---------------+-----------+-------------
testpartition | cluster1_name | testfiled | null
Could you someone explain why? Also let me know the solution to solve this, I expect 'false' not 'null'
Cassandra is not like the traditional SQL databases. It does not store rows in tables. The best way to think about Cassandra's data model is to imagine a sortedMap<rowKey, map<columnKey, value>>.
This means that any particular row is not required to have the same fields/columns as any other one. In your example the inserted row simply does not have a property named testboolean.
To understand more I can recommend referring here.
And no, you cannot set a default value for a column (or rather you can do it only on application side).
The structure of my column family is something like
CREATE TABLE product (
id UUID PRIMARY KEY,
product_name text,
product_code text,
status text,//in stock, out of stock
mfg_date timestamp,
exp_date timestamp
);
Secondary Index is created on status, mfg_date, product_code and exp_date fields.
I want to select the list of products whose status is IS (In Stock) and the manufactured date is between timestamp xxxx to xxxx.
So I tried the following query.
SELECT * FROM product where status='IS' and mfg_date>= xxxxxxxxx and mfg_date<= xxxxxxxxxx LIMIT 50 ALLOW FILTERING;
It throws error like No indexed columns present in by-columns clause with "equals" operator.
Is there anything I need to change in the structure? Please help me out. Thanks in Advance.
cassandra is not supporting >= so you have to change the value and have to use only >(greater then) and <(lessthen) for executing query.
You should have at least one "equals" operator on one of the indexed or primary key column fields in your where clause, i.e. "mfg_date = xxxxx"
Short version: Is it possible to query for all timeuuid columns corresponding to a particular date?
More details:
I have a table defined as follows:
CREATE TABLE timetest(
key uuid,
activation_time timeuuid,
value text,
PRIMARY KEY(key,activation_time)
);
I have populated this with a single row, as follows (f0532ef0-2a15-11e3-b292-51843b245f21 is a timeuuid corresponding to the date 2013-09-30 22:19:06+0100):
insert into timetest (key, activation_time, value) VALUES (7daecb80-29b0-11e3-92ec-e291eb9d325e, f0532ef0-2a15-11e3-b292-51843b245f21, 'some value');
And I can query for that row as follows:
select activation_time,dateof(activation_time) from timetest where key=7daecb80-29b0-11e3-92ec-e291eb9d325e
which results in the following (using cqlsh)
activation_time | dateof(activation_time)
--------------------------------------+--------------------------
f0532ef0-2a15-11e3-b292-51843b245f21 | 2013-09-30 22:19:06+0100
Now lets assume there's a lot of data in my table and I want to retrieve all rows where activation_time corresponds to a particular date, say 2013-09-30 22:19:06+0100.
I would have expected to be able to query for the range of all timeuuids between minTimeuuid('2013-09-30 22:19:06+0100') and maxTimeuuid('2013-09-30 22:19:06+0100') but this doesn't seem possible (the following query returns zero rows):
select * from timetest where key=7daecb80-29b0-11e3-92ec-e291eb9d325e and activation_time>minTimeuuid('2013-09-30 22:19:06+0100') and activation_time<=maxTimeuuid('2013-09-30 22:19:06+0100');
It seems I need to use a hack whereby I increment the second date in my query (by a second) to catch the row(s), i.e.,
select * from timetest where key=7daecb80-29b0-11e3-92ec-e291eb9d325e and activation_time>minTimeuuid('2013-09-30 22:19:06+0100') and activation_time<=maxTimeuuid('2013-09-30 22:19:07+0100');
This feels wrong. Am I missing something? Is there a cleaner way to do this?
The CQL documentation discusses timeuuid functions but it's pretty short on gte/lte expressions with timeuuids, beyond:
The min/maxTimeuuid example selects all rows where the timeuuid column, t, is strictly later than 2013-01-01 00:05+0000 but strictly earlier than 2013-02-02 10:00+0000. The t >= maxTimeuuid('2013-01-01 00:05+0000') does not select a timeuuid generated exactly at 2013-01-01 00:05+0000 and is essentially equivalent to t > maxTimeuuid('2013-01-01 00:05+0000').
p.s. the following query also returns zero rows:
select * from timetest where key=7daecb80-29b0-11e3-92ec-e291eb9d325e and activation_time<=maxTimeuuid('2013-09-30 22:19:06+0100');
and the following query returns the row(s):
select * from timetest where key=7daecb80-29b0-11e3-92ec-e291eb9d325e and activation_time>minTimeuuid('2013-09-30 22:19:06+0100');
I'm sure the problem is that cqlsh does not display milliseconds for your timestamps
So the real timestamp is something like '2013-09-30 22:19:06.123+0100'
When you call maxTimeuuid('2013-09-30 22:19:06+0100') as milliseconds are missing, zero is assumed so it is the same as calling maxTimeuuid('2013-09-30 22:19:06.000+0100')
And as 22:19:06.123 > 22:19:06.000 that causes record to be filtered out.
Not directly related to answer but as an additional addon to #dimas answer.
cqlsh (version 5.0.1) seem to show the miliseconds now
system.dateof(id)
---------------------------------
2016-06-03 02:42:09.990000+0000
2016-05-28 17:07:30.244000+0000