Multiple columns from a table into one, large column? - sql

I don't know what in the world is the best way to go about this. I have a very large array of columns, each one with 1-25 rows associated with it. I need to be able to combine all into one large column, skipping blanks if at all possible. Is this something that Access can do?
a b c d e f g h
3 0 1 1 1 1 1 5
3 5 6 8 8 3 5
1 1 2 2 1 5
4 4 2 1 1 5
1 5
there are no blanks within each column, but each column has a different number of numbers in it. they need to be added from left to right so a,b, c, d, e, f. And the 0 from be needs to be in the first blank cell after the second 3 in A. And the first 5 in H needs to be directly after the 1 in g, with no blanks.


So you want a result like:
3
3
0
5
1
4
1
6
1
4
etc?
Here is how I would approach the problem. Insert your array into a work table with an autonumber column (important to retain the order the data is in, databases do not guarnatee an order unless you can give them something to sort on) called id
as well as the array columns.
Create a final table with an autonumber column (see above note on why you need an automnumber) and the column you want as you final table.
Run a separate insert statment for each column in your work table and run them in the order you want the data.
so the inserts would look something like:
insert table2 (colA)
select columnA from table1 order by id
insert table2 (colA)
select columnB from table1 order by id
insert table2 (colA)
select columnC from table1 order by id
Now when you do select columnA from table2 order by id you should have the results you need.

Related

Create a table with unknown columns SQL

I have a table that looks like this
ID
Steps
Letters
1
1
a
1
2
e
1
3
b
2
1
c
2
2
d
3
1
b
3
2
a
And a query that consists of the output
a
b
d
My goal is to create a table/ modify the first one to get rid of the letter column, and instead, have N additional columns (where N is the number of rows in the second query above) and the output is 1 if the last step for that ID was that specific letter, 0 if that letter was in any step, and NULL if it never was. Making a table like this
ID
a
b
d
1
0
1
NULL
2
NULL
NULL
1
3
1
0
NULL
I assume pivoting makes sense as a way to approach it, but I don't even know where to begin

Mapping columns in oracle-sql

Table:
column 1 column 2 column 3
2 two 3
5 five 8
3 three 10
8 eight 11
12 one 15
I want to create a new column column 4like below:
column 1 column 2 column 3 column 4
2 two 3 three
5 five 8 eight
3 three 10
8 eight 11
12 one 15
I want to map column 3 and column 1 and if there's a match column 4 takes values of column 2.
Example: Value 3 in column 3 is present in column 1, so column 4 will take corresponding column 3 value three.
Thanks!

This looks like a left join:
select t.*, tt.column2 as column4
from table1 t left join
table1 tt
on t.column3 = tt.column1;
EDIT:
If you want to set the value, you can use update:
update table1 t
set column4 = (select tt.column2 from table1 tt where t.column3 = tt.column1)
where exists (select 1 from table1 tt where t.column3 = tt.column1);
However, this seems silly. You can easily get the value in the table using an explicit join or hiding the logic in a view.

Get row counts for different lookup values

A temp table has 700+ records with a PK. 12 columns contain Id values from lookup tables. Each lookup table has 4-8 records in it. How can I get a record count for each Id value in table LookupA that has a relationship via the PK to Id values in every other lookup table? Each lookup value in each lookup table needs to compared for a record count to every other lookup table and value.
I can write a SQL statement to get specific values for specific columns, but that's a long exercise and will slow down the proc.
Here's a sample of the data.
PK LookupA LookupB LookupC
1 1 1 3
2 1 2 3
3 1 3 2
4 2 4 2
5 4 1 1
6 3 2 1
7 2 3 3
8 4 4 3
9 4 3 2
10 1 1 2
The results need to compare LookupA with LookupB and LookupC to get a row count.
Table Value LookupB 1 2 3 4 LookupC 1 2 3
LookupA 1 2 1 1 0 0 2 2
2 0 0 1 1 0 1 1
3 0 1 0 0 1 0 0
4 1 0 1 1 1 1 1
Then LookupB would be compared to LookupA and LookupC.
And LookupC would be compared to LookupA and LookupB.

With this code you can get the numbers for all combinations of A,B and C in pairs:
select 'A-B' as Combination, LookupA, LookupB, count(*) as NumRecords
from table
group by Combination,LookupA, LookupB
UNION
select 'A-C' as Combination, LookupA, LookupC, count(*) as NumRecords
from table
group by Combination,LookupA, LookupC
UNION
select 'B-C' as Combination, LookupB, LookupC, count(*) as NumRecords
from table
group by Combination,LookupB, LookupC
After this, if you want to see all the values for LookupA comparing to B and C just
look for Combinations A-B and A-C

If I understand correctly, your temp table contains foreign keys to other tables, so why not simply use joins? Something like this.
SELECT COUNT(DISTINCT lookupA.id) as CountA
, COUNT(DISTINCT lookupB.id) as CountB
, etc...
FROM #temp_table t
LEFT OUTER JOIN lookupA a on a.id = t.lookupA
LEFT OUTER JOIN lookupB b on b.id = t.lookupB
...etc
I would suggest reviewing the design if possible. Having so many small tables complicates things, is it not possible to consolidate this and just have one lookup table? You could have an additional field "LookupType" and all the lookups could be in the same place which would make retrieval much simpler.

I used a slight derivative of the statement below without any UNIONs to get me where I wanted to go.
/*
select 'A-B' as Combination, LookupA, LookupB, count(*) as NumRecords
from table
group by Combination, LookupA, LookupB
*/
I used a variable and a WHILE loop to place the various summaries where they need to be.

Using VBA ADO on Excel, I am looking for an Update query to get an univocal, 1 to 1 match

I have a table similar to the following (tab1):
ID Descr Related_ID
1 a 2
2 a 1
3 a 1
4 a 1
5 b 6
6 b 5
7 b 5
8 b 5
my query is something like:
Update [tab1] as T1 INNER JOIN [tab1] as t2
ON t1.[Descr] = t2.[Descr]
SET t1.[Related_ID] = t2.[ID]
WHERE t1.[ID] <> t1.[Related_ID]
the idea is to create couple/pair between the rows of the table to get for each line one on only one ID of another line.
What the query is actually doing is overwriting each time Related_ID, with the latter table2 ID.
Instead of just use any ID only once.
The result I would like is like:
ID Descr Related_ID
1 a 2
2 a 1
3 a 4
4 a 3
5 b 6
6 b 5
7 b 8
8 b 7
I would like to create a couple / pair of element where the related_id of one is the ID of the other and viceversa.
Could you help me please?
PS:
A. I am using vba adodb on excel not on access
B. I need to maintain a good degree of efficiency, if I would implement sub query such as WHERE not [ID] IN (SELECT [ID] FROM [tab2] WHERE ...)
the efficiency will be highly impacted (from few seconds to half an hour) as the table has hundreds of rows
thanks

Get rows with single values using SQlite

By using SQlite, I'd like to get all rows that show in a specific column only one single distinct value. Like from following table:
A B
1 2
2 1
3 2
4 3
5 1
6 1
7 2
8 4
9 2
Here I'd like to get only row Nr. 4 an 8 as there values (3 and 4) occur only once in the entire column.

You could use a query like this:
SELECT *
FROM mytable
WHERE B IN (SELECT B FROM mytable GROUP BY B HAVING COUNT(DISTINCT A)=1)
Please see fiddle here.
Subquery will return all B values that are present only once (you could also use HAVING COUNT(*)=1 in this case), the outer query will return all rows where B is returned by the subquery.