(P.S. I am still learning SQL and you can consider me a newbie)
I have 2 sample tables as follows:
Table 1
|Profile_ID| |Img_Path|
Table 2
|Profile_ID| |UName| |Default_Title|
My scenario is, from the 2nd table, i need to fetch all the records that contain a certain word, for which i have the following query :
Select Profile_Id,UName from
Table2 Where
Contains(Default_Title, 'Test')
ORDER BY Profile_Id
OFFSET 5 ROWS
FETCH NEXT 20 ROWS ONLY
(Note that i am setting the OFFSET due to requirements.)
Now, the scenario is, as soon as i retrieve 1 record from the 2nd table, i need to fetch the record from the 1st table based on the Profile_Id.
So, i need to return the following 2 results in one single statement :
|Profile_Id| |Img_Path|
|Profile_Id| |UName|
And i need to return the results in side-by-side columns, like :
|Profile_Id| |Img_Path| |UName|
(Note i had to merge 2 Profile_Id columns into one as they both contain same data)
I am still learning SQL and i am learning about Union, Join etc. but i am a bit confused as to which way to go.
You can use join:
select t1.*, t2.UName
from table1 t1 join
(select Profile_Id, UName
from Table2
where Contains(Default_Title, 'Test')
order by Profile_Id
offset 5 rows fetch next 20 rows only
) t2
on t2.profile_id = t1.profile_id
SELECT a.Profile_Id, a.Img_Path, b.UName
FROM table1 a INNER JOIN table2 b ON a.Profile_Id=b.Profile_Id
WHERE b.Default_Title = 'Test'
Related
I have two tables as below.
Table 1
Book price
A 100
B 200
C 400
D 300
Table 2
Book price
A 100
B 200
C 400
Now I am executing below command as I want only the 4th record to get inserted into table 2. I want to add both the column names before NOT IN. what should I do?
Insert into table2 select * from table1 t1 where t1.book not in (select book from table2);
You can use NOT EXISTS along with matching the presumably primary key columns Book for both of the tables such as
INSERT INTO table2
SELECT *
FROM table1 t1
WHERE NOT EXISTS ( SELECT 0 FROM table2 WHERE Book=t1.Book);
Demo
P.S.: Should be careful about NULL values while using NOT IN operator. Moreover, using NOT IN is mostly less performant than using NOT EXISTS
I tried it and it looks fine to me.
may be you run the script twice so it will show 0 rows created in the second time.
make sure you committed the row.
I have a list of IDs
'ACE', 'ACD', 'IDs', 'IN','CD'
I also have a table similar to following structure
ID value
ACE 2
CED 3
ACD 4
IN 4
IN 4
I want a SQL query that returns a list of IDs that exists in the database and a list of IDs that does not in the database.
The return should be:
1.ACE, ACD, IN (exist)
2.IDs,CD (not exist)
my code is like this
select
ID,
value
from db
where ID is in ( 'ACE', 'ACD', 'IDs', 'IN','CD')
however, the return is 1) super slow with all kinds of IDs 2) return multiple rows with the same ID. Is there anyway using postgresql to return 1) unique ID 2) make the running faster?
Assuming no duplicates in table nor input, this query should do it:
SELECT t.id IS NOT NULL AS id_exists
, array_agg(ids.id)
FROM unnest(ARRAY['ACE','ACD','IDs','IN','CD']) ids(id)
LEFT JOIN tbl t USING (id)
GROUP BY 1;
Else, please define how to deal with duplicates on either side.
If the LEFT JOIN finds a matching row, the expression t.id IS NOT NULL is true. Else it's false. GROUP BY 1 groups by this expression (1st in the SELECT list), array_agg() forms arrays for each of the two groups.
Related:
Select rows which are not present in other table
Hmmm . . . Is this sufficient:
select ids.id,
(exists (select 1 from table t where t.id = ids.id)
from unnest(array['ACE', 'ACD', 'IDs', 'IN','CD']) ids(id);
I am using ms sql server, i have two tables below( table 1 and table 2):
table 1 table 2 result
name value ++ name data == name value data
test 10 test1 20 test 10 null
test1 null 20
I want to merge table 1 and table 2 and my expected result would be as result table , can anybody help me here ?
You can combine these using a full join:
select coalesce(t1.name, t2.name) as name, t1.value, t2.data
from t1 full join
t2
on t1.name = t2.name;
If you want to use * to select all columns in the tables, SQL Server does not offer simple way to choose unique columns (without listing all columns). SQL Server doesn't support USING.
I have two table one is having all field VARCHAR2 but other having different type for different data.
For Example :
Table One
==========================
Col 1 VARCHAR2 UNIQUE KEY
Col 2 VARCHAR2
Col 3 VARCHAR2
===========================
Table Two
==========================
Col One VARCHAR2 UNIQUE KEY
Col Two TIMESTAMP
Col Three NUMBER
==========================
we are having one mapping table. it denotes which column of Table One has to compare with which column of Table Two.
For Example
Mapping Table
==============================
Table One Table Two
==============================
Col 1 Col One
Col 2 Col Three
Col 3 Col Two
==============================
Now with the help of UNIQUE KEY of TABLE ONE we have to find same row in TABLE TWO and compare rows column by column and get changes in data.
Currently we are using java program for comparing data row by row and column by column and getting changes between data in rows with same UNIQUE KEY. it is working fine but taking too much time as we are having 100000 records in DB.
Now my question is : is there any way i can compare data at SQL level and get changes in data?
You can do it 'manually' with a query like this: It's a lot of work, but there are only three different types of checks you need to do, so it's not very complex:
select
*
from
Table1 t1
full outer join Table2 t2 on t2.ID = t1.ID
where
-- Check ID, either record does not exist in either table.
t1.ID is null or
t2.ID = null or
-- Not nullable field can be easily compared.
t1.NotNullableField1 <> t2.NotNUllableField1 or
-- Nullable field is slightly more work.
t1.NullableField1 <> t2.NullableField1 or
(t1.NullableField1 is null and t2.NullableField1 is not null) or
(t1.NullableField1 is not null and t2.NullableField1 is null)
Another solution is to use MINUS, which is a bit like UNION, only it returns a dataset minus the records in a second dataset:
select * from Table1 t1
MINUS
select * from Table2 t2
This works only one way (which might be fine for your purpose), but you can also combine it with UNION to make it bidirectional.
select
*
from
( select * from Table1
MINUS
select * from Table2)
UNION ALL
( select * from Table2
MINUS
select * from Table1)
The output of both solutions is a bit different.
In the FULL OUTER JOIN query, the IDs will be joined and the values of the matching rows will be displayed next to each other as a single row.
In the MINUS query, the result will be presented as a single dataset. If a record does not exist in either one table, it will be displayed. If a record (ID) exists in both tables, but other fields are different, you will get both rows. So it's a bit harder to compare them.
See: http://www.techonthenet.com/oracle/minus.php
Currently,I have this objective to meet. I need to query the database for certain results. After done so, I will need to compare the records:
For example: the query return me with 10 rows of records, I then need to compare: row 1 with 2, row 2 with 3, row 3 with 4 ... row 9 with 10.
The final result that I wish to have is 10 or less than 10 rows of records.
I have one approach currently. I do this within a function, hand have the variables call "previous" and "current". In a loop I will always compare previous and current which I populate through the record set using a cursor.
After I got each row of filtered result, I will then input it into a physical temporary table.
After all the results are in this temporary table. I'll do a query on this table and insert the result into a cursor and then returning the cursor.
The problem is: how can I not use a temporary table. I've search through online about using nested tables, but somehow I just could not get it working.
How to replace the temp table with something else? Or is there other approach that I can use to compare the row columns with other rows.
EDIT
So sorry, maybe I am not clear with my question. Here is a sample of the result that I am trying to achieve.
TABLE X
Column A B C D
100 300 99 T1
100 300 98 T2
100 300 97 T3
100 100 97 T4
100 300 97 T5
101 11 11 T6
ColumnA is the primary key of the table. ColumnA has duplicates because table X is an audit table that keep tracks of all changes.column D acts as the timestamp for that record.
For my query, I am only interested in changes in column A,B and D. After the query I would like to get the result as below:
Column A B D
100 300 T1
100 100 T4
100 300 T5
101 11 T6
I think Analytics might do what you want :
select col1, col2, last(col1) over (order by col1, col2) LASTROWVALUE
from table1
this way, LASTROWVALUE will contain de value of col1 for the last row, which you can directly compare to the col1 of the current row.
Look this URL for more info : http://www.orafaq.com/node/55
SELECT ROW_NUMBER() OVER(ORDER BY <Some column name>) rn,
Column1, <Some column name>, CompareColumn,
LAG(CompareColumn) OVER(ORDER BY <Some column name>) PreviousValue,
LEAD(CompareColumn) OVER(ORDER BY <Some column name>) NextValue,
case
when CompareColumn != LEAD(CompareColumn) OVER(ORDER BY <Some column name>) then CompareColumn||'-->'||LEAD(CompareColumn) OVER(ORDER BY <Some column name>)
when CompareColumn = LAG(CompareColumn) OVER(ORDER BY <Some column name>) then 'NO CHANGE'
else 'false'
end
FROM <table name>
You can use this logic in a loop to change behaviour.
Hi It's not very clear what exactly yuo want to accomplish. But maybe you can fetch the results of the original query in a PLSQL collection and use that to do your comparison.
What exactly are you doing the row comparison for? Are you looking to eliminate duplicates, or are you transforming the data into another form and then returning that?
To eliminate duplicates, look to use GROUP BY or DISTINCT functionality in your SELECT.
If you are iterating over the initial data and transforming it in some way then it is hard to do it without using a temporary table - but what exactly is your problem with the temp table? If you are concerned about the performance of a cursor then maybe you could do one outer SELECT that compares the results of two inner SELECTs - but the trick is that the second SELECT is offset by one row, so you achieve the requirement of comparing row 1 against row2, etc.
I think you are complicating things with the temp table.
It can be made using a cursor and 2 temporary variables.
Here is the pseudo code:
declare
v_temp_a%xyz;
v_temp_b%xyz;
i number;
cursor my_cursor is select xyz from xyz;
begin
i := 1;
for my_row in my_cursor loop
if (i = 1)
v_temp_a := my_row;
else
v_temp_b := v_temp_a;
v_temp_a := my_row;
/* at this point v_temp_b has the previous row and v_temp_a has the currunt row
compare them and put whatever logic you want */
end if
i := i + 1;
end loop
end