Assume you have a set as follows:
+-------+-------+
| PK | value |
+-------+-------+
| "pk1" | 24 |
+-------+-------+
1 row in set (0.105 secs)
How to get the metadata for this?
To get the metadata, all you need to do is run this command before running the query:
set RECORD_PRINT_METADATA true
Now, when you query the set
select * from test.segments
you can see additional metadata of the set, as follows:
+-------+-------+--------------------------------+------------+-------+-------+
| PK | value | {edigest} | {set} | {ttl} | {gen} |
+-------+-------+--------------------------------+------------+-------+-------+
| "pk1" | 24 | "Rn/5rHEQGWvPOSBK+vHRMyLkFyo=" | "segments" | 57 | 1 |
+-------+-------+--------------------------------+------------+-------+-------+
1 row in set (0.175 secs)
NOTE:
The command has to be run just once. It holds true for all the queries that come after it.
To go back to the default behaviour, set the argument to false
Related
The title may not be that helpful but what I am trying to do is this.
For simplicity's sake I have two tables one called logs and another called Log controls
In LOGS I have and a log event column, this is automatically populated by imported information. On the LOG CONTROLS I have a manually entered list of Log events (to match the ones coming in) and I have this table to have them assigned ID numbers and other details about the event.
What I need to do is have a column in the LOGS table which looks at the Log events, matches it to the ID from the LOG CONTROLS table and assigns the ID into the LOGS table.
I have seen a few methods of changing information in columns based of information in other tables but all of these seem to be one way checks i.e if ID = X change to VALUE FROM OTHER TABLE where as what I need is IF VALUE = X FROM OTHER TABLE CHANGE ID FIELD TO = Y FROM OTHER TABLE
Below is a mock up of the tables.
+----+-----------+----------+------------+
| ID | Date_Time | Event | Control ID|
+----+-----------+----------+------------+
| 1 | 0/0/0 | Shutdown | |
| 2 | 0/0/0 | Start up | |
| 3 | 0/0/0 | Error | |
| 4 | 0/0/0 | Info | |
| 5 | 0/0/0 | Shutdown | |
| 6 | 0/0/0 | Error | |
+----+-----------+----------+------------+
+-------------------+----------+--------+-------+
| Control ID | Event | Export | Flag |
+-------------------+----------+--------+-------+
| 1 | Shutdown | TRUE | TRUE |
| 2 | Start up | TRUE | FALSE |
| 3 | Error | TRUE | TRUE |
| 4 | Info | TRUE | FALSE |
+-------------------+----------+--------+-------+
So I need the Control ID in the first table to match the control ID from the second table depending on what the event was.
I hope this makes sense.
Any help or advice would be greatly appreciated.
From your description, it seems that a simple UPDATE statement is all you need:
update logs
set control_id = c.control_id
from log_controls as c
where c.event = logs.event;
I have to update a value in one field of a table (t1).
Current table t1 records :
| POLNAME | VALUE |
|-------------------|
| TEST_01 | Normal |
| TEST_02 | High |
| TEST_03 | Normal |
| TEST_04 | Low |
| TEST_05 | Low** |
New table t1 records expected after the update :
| POLNAME | VALUE |
|-------------------|
| REST_01 | Normal |
| REST_02 | High |
| REST_03 | Normal |
| REST_04 | Low |
| REST_05 | Low** |
I need to replace, in t1-POLNAME field, the fixed value 'TEST_' by 'REST_' for all records of table t1.
I can do one by one using an UPDATE SQL command, but my goal is to replace all records using one SQL command.
You can use the REPLACE SQL FUNCTION.
UPDATE t1 SET POLNAME=REPLACE(POLNAME, 'TEST','REST');
You can use the REPLACE Syntax
UPDATE t1 SET POLNAME=REPLACE(POLNAME, 'TEST','REST');
I have a table in Access named Spells which holds patient spells (where a patient has a spell within a hospital). It's structure is as below:
| ID | SpellID | MultipleSpell | FirstSpell | LastSpell |
|----|---------|---------------|------------|-----------|
| 1 | 1 | False | | |
| 2 | 2 | True | | |
| 3 | 2 | True | | |
| 4 | 3 | False | | |
| 5 | 4 | False | | |
| 6 | 5 | True | | |
| 7 | 5 | True | | |
| 8 | 5 | True | | |
The MultipleSpell column indicates that there are multiple occurrences of the spell within the table.
I'd like to run query which would update the FirstSpell column to True for records with the IDs of 1,2,4,5,6. So basically, where a Spell is the first one in the table, it should be marked, in the FirstSpell column.
I would also then like to update the LastSpell column to True for records with the IDs of 1,3,4,5,8.
The reasoning for this (if you're interested) is that the table links to a separate table containing the name of wards. It would be useful to link to this other table and indicate whether the ward is the admitting ward (FirstSpell) or the discharging ward (LastSpell)
You can update the first using:
update spells
set firstspell = 1
where id = (select min(id)
from spells as s2
where spells.spellid = s2.spellid
);
Similar logic (using max()) can be used for the last spell.
I have a log table with web log entries which have a session ID. I also have a session table summarizing sessions from the previous table. So I have to run some update SQL statement but I don't get how to construct a SQL statement for a field named "session_length". In this field I hope to assign the number of events in that particular session.
Let's say I have the following log table:
| Session ID | Timestamp | Action | ...
| 1 | 00:00:00 | get | ...
| 2 | 00:00:00 | get | ...
| 1 | 00:00:01 | get | ...
| 1 | 00:00:02 | get | ...
| 2 | 00:00:02 | get | ...
In the session table, I would like to have the following values for session_length field:
| Session ID | session_length | ...
| 1 | 3 | ...
| 2 | 2 | ...
I am not sure whether this can be done by a single query but I would like to see if this can be done by a single SQL query using update. In particular, I am using PostgresSQL in AWS RedShift.
You can do this with a correlated subquery in the update statement:
update sessions
set session_length = (select count(*)
from log
where log.sessionid = sessions.sessionid
)
Sorry for the title, perhaps it's not very clear.
I have some SQL queries in a script that depend on each other.
The script uses a temporary table in which the data is inserted (the #temp_data table).
This is the expected output:
___________________________________
| speed1 | speed2 | distance |
| 1 | NULL | 10 |
| 3 | NULL | 40 |
| 5 | NULL | 90 |
| NULL | 1 | 10 |
| NULL | 3 | 40 |
| NULL | 5 | 90 |
Here is the query structure (I didn't include the actual query since it's too big):
-- First group
queryForSpeed1
queryToUpdateDistanceBasedOnSpeed1
-- Second group
queryForSpeed2
queryToUpdateDistanceBasedOnSpeed2
If I run the first group of queries (queryForSpeed1 and queryToUpdateDistanceBasedOnSpeed1) separately from the second group then I get the expected output: only the speed1 and distance columns contain data:
___________________________________
| speed1 | speed2 | distance |
| 1 | NULL | 10 |
| 3 | NULL | 40 |
| 5 | NULL | 90 |
| NULL | NULL | NULL |
| NULL | NULL | NULL |
| NULL | NULL | NULL |
The same happens when I run the second group:
___________________________________
| speed1 | speed2 | distance |
| NULL | NULL | NULL |
| NULL | NULL | NULL |
| NULL | NULL | NULL |
| NULL | 1 | 10 |
| NULL | 2 | 40 |
| NULL | 3 | 90 |
BUT, when I run both groups: all the distances are NULL:
___________________________________
| speed1 | speed2 | distance |
| 1 | NULL | NULL |
| 3 | NULL | NULL |
| 5 | NULL | NULL |
| NULL | 1 | NULL |
| NULL | 2 | NULL |
| NULL | 3 | NULL |
I believe this is somehow related to transaction management and temporary tables, although I wasn't able to find anything relevant to solve the problem on Google.
From what I've read, SQL Server keeps a transaction log where it stores every update, insert and whatever... when it arrives at the end of the script it actually does all those insertions and updates.
So the update I did for the distance column finds all the speeds as being NULL because the data wasn't yet inserted in the temporary table from the previous updates, but at the end of the query the speeds are inserted in the table so that's why they are visible.
I played a bit with the GO statement to execute my script in batches, but no luck so far...
What am I doing wrong? Can someone point me in the right direction, please?
EDIT
Here is the actual query.
The problem is not related to transactions, but rather to the way you conduct updates to #temp_speed_profile. The second pass through #temp_speed_profile retrieves all six records. Speed_new is null in first record of Voyage_Id, consequently #distance becomes null. As you retain the value of #distance in next turn, it remains null.
Problem goes away when using different temporary tables because second pass works on second set of data only.
A note on cursors - when defining one make sure to add local and fast_forward. Local because it is limiting cursors' scope, and fast_forward to optimize fetches.
It is almost certainly caused by the way you have written your queries.
To confirm, just rewrite your queries using #temp_data1 and #temp_data2, rather than a single table #temp_data.