I have below table with 160,000 rows. When I use SELECT ID FROM mytable WHERE id NOT IN ( SELECT max(id) FROM mytable GROUP BY user_id); query is running very long and not finishing (I wait for 1 Hr) but when I use delete FROM mytable WHERE id NOT IN (SELECT max(id) FROM mytable GROUP BY user_id); query is running in 0.5 seconds. Why??
---------------------------------------------------------------------------------------------------
| id | MyTimestamp | Name | user_id ...
----------------------------------------------------------------------------------------------------
| 0 | 1657640396 | John | 123581 ...
| 1 | 1657638832 | Tom | 168525 ...
| 2 | 1657640265 | Tom | 168525 ...
| 3 | 1657640292 | John | 123581 ...
| 4 | 1657640005 | Jack | 896545 ...
-----------------------------------------------------------------------------------------
I'm trying to get some precise row counts for all tables, given that some have deleted rows. I have been using sys.storage.count. But this seems to count the deleted ones also.
I assume using sys.storage would be simpler and faster than looping through count(*) queries, though both strategies may be fine in practice.
Maybe there is some column that counts modifications so I could just subtract the two counts?
If all you need to know is the number of actual rows in a table, I'd recommend just using a count(*) query. It's very fast. Even if you have N tables, it's easy to do a count(*) for each table.
sys.storage gives you information from the raw storage. With that, you can get pretty low-level information, but it has some edges. sys.storage.count returns the count in the storage, hence, indeed, it includes the delete rows since they are not actually deleted. As of Jul2021 version of MonetDB, deleted rows are automatically overwritten by new inserts (i.e. auto-vacuuming). So, to get the actual row count, you need to look up the 'deletes' from sys.deltas('<schema>', '<table>'). For instance:
sql>create table tbl (id int, city string);
operation successful
sql>insert into tbl values (1, 'London'), (2, 'Paris'), (3, 'Barcelona');
3 affected rows
sql>select * from tbl;
+------+-----------+
| id | city |
+======+===========+
| 1 | London |
| 2 | Paris |
| 3 | Barcelona |
+------+-----------+
3 tuples
sql>select schema, table, column, count from sys.storage where table='tbl';
+--------+-------+--------+-------+
| schema | table | column | count |
+========+=======+========+=======+
| sys | tbl | city | 3 |
| sys | tbl | id | 3 |
+--------+-------+--------+-------+
2 tuples
sql>select id, deletes from sys.deltas ('sys', 'tbl');
+-------+---------+
| id | deletes |
+=======+=========+
| 15569 | 0 |
| 15570 | 0 |
+-------+---------+
2 tuples
After we delete one row, the actual row count is sys.storage.count - sys.deltas ('sys', 'tbl').deletes:
sql>delete from tbl where id = 2;
1 affected row
sql>select * from tbl;
+------+-----------+
| id | city |
+======+===========+
| 1 | London |
| 3 | Barcelona |
+------+-----------+
2 tuples
sql>select schema, table, column, count from sys.storage where table='tbl';
+--------+-------+--------+-------+
| schema | table | column | count |
+========+=======+========+=======+
| sys | tbl | city | 3 |
| sys | tbl | id | 3 |
+--------+-------+--------+-------+
2 tuples
sql>select id, deletes from sys.deltas ('sys', 'tbl');
+-------+---------+
| id | deletes |
+=======+=========+
| 15569 | 1 |
| 15570 | 1 |
+-------+---------+
2 tuples
After we insert a new row, the deleted row is overwritten:
sql>insert into tbl values (4, 'Praag');
1 affected row
sql>select * from tbl;
+------+-----------+
| id | city |
+======+===========+
| 1 | London |
| 4 | Praag |
| 3 | Barcelona |
+------+-----------+
3 tuples
sql>select schema, table, column, count from sys.storage where table='tbl';
+--------+-------+--------+-------+
| schema | table | column | count |
+========+=======+========+=======+
| sys | tbl | city | 3 |
| sys | tbl | id | 3 |
+--------+-------+--------+-------+
2 tuples
sql>select id, deletes from sys.deltas ('sys', 'tbl');
+-------+---------+
| id | deletes |
+=======+=========+
| 15569 | 0 |
| 15570 | 0 |
+-------+---------+
2 tuples
So, the formula to compute the actual row count (sys.storage.count - sys.deltas ('sys', 'tbl').deletes) is generally applicable. sys.deltas() keeps stats for every column of a table, but the count and deletes are table wide, so you only need to check one column.
I have a SQL Server table like this
+----+-----------+------------+
| id | acoount | date |
+----+-----------+------------+
| | John | 2/6/2016 |
| | John | 2/6/2016 |
| | John | 4/6/2016 |
| | John | 4/6/2016 |
| | Andi | 5/6/2016 |
| | Steve | 4/6/2016 |
+----+-----------+------------+
i want insert the id coloumn like this.
+-----------+-----------+------------+
| id | acoount | date |
+-----------+-----------+------------+
| 020616001 | John | 2/6/2016 |
| 020616002 | John | 2/6/2016 |
| 040616001 | John | 4/6/2016 |
| 040616002 | John | 4/6/2016 |
| 050616001 | Andi | 5/6/2016 |
| 040616003 | Steve | 4/6/2016 |
+-----------+-----------+------------+
I want to generate id number of the date provided like this. 02+06+16(from date)+001 = 020616001. if have same date, id + 1.
I have tried but still failed .
I want make it in oracle sql develop.
Someone help me.
Thanks.
Try the below SQL as per the given data, Its in SQL Server 2012....
select REPLACE(CONVERT(VARCHAR(10),convert(date,t.[date]), 101), '/', '')
+'00'+convert(varchar(2),row_number()over(partition by account,[date] order by t.[date])) as ID,
t.account,
t.date
from (values ('John','2/6/2016'),
('John','2/6/2016'),
('John','4/6/2016'),
('John','4/6/2016'),
('Andi','5/6/2016'),
('Steve','4/6/2016'))T(account,[date])
Update your table using statement .
update table set id= replace(CONVERT(VARCHAR(10),CONVERT(datetime ,date,103),3) ,'/', '') + Right('00'+convert(varchar(2),row_number()over(partition by account,[date] order by t.[date])) ,3)
MySql
i can give you the logic of 020616001 this part right now .......
for same id +1 i have to work on it....that i ll let u know after my work
insert into table_name(id)
select concat
(
if(length (day(current_date))>1,day(current_date),Concat(0,day(current_date))),
if(length (month(current_date))>1,month(current_date),Concat(0,month(current_date))),
(right(year(current_date),2)),'001'
)as id
you cannot convert your dates column to datetime type in normal way because it is dd/mm/yyyy.
Try this,
declare #t table(acoount varchar(50),dates varchar(20))
insert into #t values
('John','2/6/2016')
,('John','2/6/2016')
,('John','4/6/2016')
,('John','4/6/2016')
,('Andi','5/6/2016')
,('Steve','4/6/2016')
;With CTE as
(select * , SUBSTRING(dates,0,charindex('/',dates)) dd
,SUBSTRING(stuff(dates,1,charindex('/',dates),''),0, charindex('/',stuff(dates,1,charindex('/',dates),''))) MM
,right(dates,2) yy
from #t
)
,CTE1 as
(
select *
,ROW_NUMBER()over(partition by yy,mm,dd order by yy,mm,dd)rn from cte c
)
select *, REPLICATE('0',2-len(dd))+cast(dd as varchar(2))
+REPLICATE('0',2-len(MM))+cast(MM as varchar(2))
+yy+REPLICATE('0',3-len(rn))+cast(rn as varchar(2))
from cte1
I have one table like this (report)
--------------------------------------------------
| user_id | Department | Position | Record_id |
--------------------------------------------------
| 1 | Science | Professor | 1001 |
| 1 | Maths | | 1002 |
| 1 | History | Teacher | 1003 |
| 2 | Science | Professor | 1004 |
| 2 | Chemistry | Assistant | 1005 |
--------------------------------------------------
I'd like to have the following result
---------------------------------------------------------
| user_id | Department+Position |
---------------------------------------------------------
| 1 | Science,Professor;Maths, ; History,Teacher |
| 2 | Science, Professor; Chemistry, Assistant |
---------------------------------------------------------
That means I need to preserve the empty space as ' ' as you can see in the result table.
Now I know how to use LISTAGG function but only for one column. However, I can't exactly figure out how can I do for two columns at the sametime. Here is my query:
SELECT user_id, LISTAGG(department, ';') WITHIN GROUP (ORDER BY record_id)
FROM report
Thanks in advance :-)
It just requires judicious use of concatenation within the aggregation:
select user_id
, listagg(department || ',' || coalesce(position, ' '), '; ')
within group ( order by record_id )
from report
group by user_id
i.e. aggregate the concatentation of department with a comma and position and replace position with a space if it is NULL.
This is a bit hard to explain in words ... I'm trying to calculate a sum of grouped distinct values in a matrix. Let's say I have the following data returned by a SQL query:
------------------------------------------------
| Group | ParentID | ChildID | ParentProdCount |
| A | 1 | 1 | 2 |
| A | 1 | 2 | 2 |
| A | 1 | 3 | 2 |
| A | 1 | 4 | 2 |
| A | 2 | 5 | 3 |
| A | 2 | 6 | 3 |
| A | 2 | 7 | 3 |
| A | 2 | 8 | 3 |
| B | 3 | 9 | 1 |
| B | 3 | 10 | 1 |
| B | 3 | 11 | 1 |
------------------------------------------------
There's some other data in the query, but it's irrelevant. ParentProdCount is specific to the ParentID.
Now, I have a matrix in the MS Report Designer in which I'm trying to calculate a sum for ParentProdCount (grouped by "Group"). If I just add the expression
=Sum(Fields!ParentProdCount.Value)
I get a result 20 for Group A and 3 for Group B, which is incorrect. The correct values should be 5 for group A and 1 for group B. This wouldn't happen if there wasn't ChildID involved, but I have to use some other child-specific data in the same matrix.
I tried to nest FIRST() and SUM() aggregate functions but apparently it's not possible to have nested aggregation functions, even when they have scopes defined.
I'm pretty sure there is some way to calculate the grouped distinct sum without needing to create another SQL query. Anyone got an idea how to do that?
Ok I got this sorted out by adding a ROW_NUMBER() function my SQL query:
SELECT Group, ParentID, ROW_NUMBER() OVER (PARTITION BY ParentID ORDER BY ChildID ASC) AS Position, ChildID, ParentProdCount FROM Table
and then I replaced the SSRS SUM function with
=SUM(IIF(Position = 1, ParentProdCount.Value, 0))
Put a grouping over the ParentID and use a summation over that group,
eg:
if group over ParentID = "ParentIDGroup"
then
column sum of ParentPrdCount = SUM(Fields!ParentProdCount.Value,"ParentIDGroup")