Alternative way to write IN clause in GQL - google-cloud-datastore

How to write below query in GQL
select * from test WHERE lid=1234 AND status IN (1,7,8) order by sent_datetime DESC
Exception while executing above query :GQL query error: Encountered "IN" at line 1, column 46. Was expecting one of: "contains", "has", "is", "=", "<", "<=", ">", ">=", ".", "("
And all the columns are indexed.
Thanks

IN is a feature of some client libraries and isn't strictly part of the GQL language of the server. You can do the same thing that the client libraries do to emulate this feature by issuing a query for each value in the IN clause and dedup results.
So this:
select * from test WHERE lid=1234 AND status IN (1,7,8) order by sent_datetime DESC
Would become these:
select * from test WHERE lid=1234 AND status = 1 order by sent_datetime DESC
select * from test WHERE lid=1234 AND status = 7 order by sent_datetime DESC
select * from test WHERE lid=1234 AND status = 8 order by sent_datetime DESC

Related

Snowflake, Recursive CTE , Getting error String 'AAAA_50>BBBB_47>CCCC_92' is too long and would be truncated in 'CONCAT'

I am creating a recursive CTE in snowflake for getting complete path an getting following error:
String 'AAAA_50>BBBB_47>CCCC_92' is too long and would be truncated in 'CONCAT'
My script is as follows: (it works fine for 2 levels, starts failing for 3rd level)
with recursive plant
(child_col,parent_col,val )
as
(
select child_col, '' parent_col , trim(child_col) from My_view
where condition1 = 'AAA'
union all
select A.child_col,A.parent_col,
concat(trim(A.child_col),'>')||trim(val)
from My_view A
JOIN plant as B ON trim(B.child_col) = trim(A.parent_col)
)
select distinct * from plant
Most likely the child_col data type is defined as VARCHAR (N), this type is being passed on. Because CONCAT Returns:
The data type of the returned value is the same as the data type of
the input value(s).
Try to explicitly cast a type to a string like this cast(trim(child_col) as string):
Full code:
with recursive plant (child_col,parent_col,val )
as (
select child_col, '' parent_col , cast(trim(child_col) as string)
from My_view
where condition1 = 'AAA'
union all
select A.child_col, A.parent_col, concat(trim(A.child_col),'>')||trim(val)
from My_view A
join plant as B ON trim(B.child_col) = trim(A.parent_col)
)
select distinct * from plant
Remember that recursion in Snowflake is limited to 100 loops by default.
If you want to increase them, you need to contact support.
Reference: CONCAT Troubleshooting a Recursive CTE

How to conditionally change ascendancy?

I want conditionally orderBy my query. All completed tasks (completed 1) should be below uncompleted and ordered by completion time and uncompleted task should be ordered by priority value. I am getting this with following statement:
orderBy = TaskTable.COLUMN_TASK_COMPLETED + " ASC, CASE " +TaskTable.COLUMN_TASK_COMPLETED+" WHEN 0 THEN " +TaskTable.COLUMN_TASK_PRIORITY +" WHEN 1 THEN "+TaskTable.COLUMN_TASK_COMPLETED_TIME + " END DESC";
Now, I want to change it, such way that priority is ordered with ASC attribute and completed_time is ordered with DESC attribute.
I tried:
orderBy = TaskTable.COLUMN_TASK_COMPLETED + " ASC, CASE " +TaskTable.COLUMN_TASK_COMPLETED+" WHEN 0 THEN " +TaskTable.COLUMN_TASK_PRIORITY +" ASK WHEN 1 THEN "+TaskTable.COLUMN_TASK_COMPLETED_TIME + " DESC END";
But it returns error:
Caused by: android.database.sqlite.SQLiteException: near "ASC": syntax error (code 1): , while compiling: SELECT * FROM task_table WHERE (task_name LIKE ? ) ORDER BY task_completed ASC, CASE task_completed WHEN 0 THEN task_priority ASC WHEN 1 THEN task_completed_time DESC END
How to fix it?
The ASC/DESC specifications can be applied only to the top-level expressions used in the ORDER BY clause.
When you have a numeric column, you can simply negate its values, i.e., sort not by X but by -X.

query with max and second factor [duplicate]

I have:
TABLE MESSAGES
message_id | conversation_id | from_user | timestamp | message
I want:
1. SELECT * WHERE from_user <> id
2. GROUP BY conversation_id
3. SELECT in every group row with MAX(timestamp) **(if there are two same timestamps in a group use second factor as highest message_id)** !!!
4. then results SORT BY timestamp
to have result:
2|145|xxx|10000|message
6|1743|yyy|999|message
7|14|bbb|899|message
with eliminated
1|145|xxx|10000|message <- has same timestamp(10000) as message(2) belongs to the same conversation(145) but message id is lowest
5|1743|me|1200|message <- has message_from == me
example group with same timestamp
i want from this group row 3 but i get row 2 from query
SELECT max(message_timestamp), message_id, message_text, message_conversationId
FROM MESSAGES
WHERE message_from <> 'me'
GROUP BY message_conversationId
ORDER by message_Timestamp DESC
what is on my mind to do union from message_id & timestamp and then get max???
Your query is based on non-standard use of GROUP BY (I think SQLite allows that only for compatibility with MySQL) and I'm not at all sure that it will produce determinate results all the time.
Plus it uses MAX() on concatenated columns. Unless you somehow ensure that the two (concatenated) columns have fixed widths, the results will not be accurate for that reason as well.
I would write the query like this:
SELECT
m.message_timestamp,
m.message_id,
m.message_text,
m.message_conversationId
FROM
( SELECT message_conversationId -- for every conversation
FROM messages as m
WHERE message_from <> 'me'
GROUP BY message_conversationId
) AS mc
JOIN
messages AS m -- join to the messages
ON m.message_id =
( SELECT mi.message_id -- and find one message id
FROM messages AS mi
WHERE mi.message_conversationId -- for that conversation
= mc.message_conversationId
AND mi.message_from <> 'me'
ORDER BY mi.message_timestamp DESC, -- according to the
mi.message_id DESC -- specified order
LIMIT 1 -- (this is the one part)
) ;
Try below sql to achieve your purpose by group by twice.
select m.*
from
Messages m
-- 3. and then joining to get wanted output columns
inner join
(
--2. then selecting from this max timestamp - and removing duplicates
select conversation_id, max(timestamp), message_id
from
(
-- 1. first select max message_id in remainings after the removal of duplicates from mix of cv_id & timestamp
select conversation_id, timestamp, max(message_id) message_id
from Messages
where message <> 'me'
group by conversation_id, timestamp
) max_mid
group by conversation_id
) max_mid_ts on max_mid_ts.message_id = m.message_id
order by m.message_id;
http://goo.gl/MyZjyU
ok it was more simple than I thought:
basically to change select from:
max(message_timestamp)
to:
max(message_timestamp || message_id)
or max(message_timestamp + message_id)
so it will search for max on concatenation of timestamp and message_id
ps. after a digging - it's working only if message id is growing with timestamp ( order of insertion is preserved )
edit:
edit2 :
so why it works ?
SELECT max(message_timestamp+message_id), message_timestamp, message_id, message_conversationId, message_from,message_text
FROM MESSAGES
WHERE message_conversationId = 1521521
AND message_from <> 'me'
ORDER by message_Timestamp DESC

Trouble with SQLite : Query Error: near FROM: syntax error Unable to execute statement

I keep getting this error in SQLite:
Query Error: near "FROM": syntax error Unable to execute statement
SELECT Name, CourseId
FROM Lecturer JOIN Lecture ON Lecturer.LecturerId = Lecture.LecturerId
JOIN (SELECT CourseId
FROM Course
WHERE EXISTS (SELECT *
FROM Exam
WHERE Exam.CourseId = Course.CourseId
AND (SELECT COUNT *
FROM Exam
WHERE Grade > 6)
<
(SELECT COUNT *
FROM Exam
WHERE Grade < 6)))
USING Course.Id
I would normally assign the inline view an alias, e.g FOO, and join an outer table to the inline view with an on... clause:
select * from x
join
(
select someColumn, someOtherColumn...
) as FOO
on x.somecolumn = FOO.somecolumn
I would go about it this way:
select lecture.*, FOO.courseid
from lecture
join lecturer on lecture.lecturerid = lecturer.lecturerid
join
(
you inline view selecting the courses
) as FOO
on lecture.courseid = FOO.courseid
COUNT is a function, you need parens around the *
Such as:
COUNT(*)

SQL Select fields with a value of 'Y' and order by date descending, then select all others and order by another field ascending

I am generating an SQL query:
SELECT * FROM ToDoList
WHERE ws_status <> 'Completed'
AND (user_id= 'TESTUSR' OR ww_cover='TESTUSR'
OR (ws_status = 'Orphan' AND wwt_workgroupid IN (108)))
**ORDER BY psc_alt_code ASC**
And I need to list all results with wi_urgent set to 'Y' and order them by date Desc *first and then list all other results ordered by psc_alt_code descending* so I thought something like this would suffice:
ORDER BY (wi_urgent = 'Y') DESC, psc_alt_code ASC
I am getting SqlClient.SqlException: Incorrect syntax near '=' error when trying to run that query. Please note that I am querying an SQL View if that makes a difference?
You can use a case expression in the order by
SELECT * FROM ToDoList
WHERE ws_status <> 'Completed'
AND (user_id= 'TESTUSR' OR ww_cover='TESTUSR'
OR (ws_status = 'Orphan' AND wwt_workgroupid IN (108)))
ORDER BY CASE WHEN wi_urgent = 'Y' THEN 0 ELSE 1 END ASC
,psc_alt_code
I don't think you can do wi_urgent = 'Y' in an ORDER BY.
Since you're looking for all results with wi_urgent, try adding it to the WHERE clause:
SELECT * FROM ToDoList
WHERE ws_status <> 'Completed'
AND (user_id= 'TESTUSR' OR ww_cover='TESTUSR'
OR (ws_status = 'Orphan' AND wwt_workgroupid IN (108)))
AND wi_urgent = 'Y'
ORDER BY wi_urgent DESC,
psc_alt_code ASC

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