I have two tables (with the same schema)
Table1
id title D0 D1 D2 D3
------------------------------------
1 Title1 0.12 3.23 4.90 -0.12
1 Title1 0.22 0.32 -4.90 0.12
1 Title1 0.13 1.24 3.50 -0.22
...
1 TitleN 1.22 2.33 3.90 -1.56
and
Table2
id title D0 D1 D2 D3
------------------------------------
1 Title1 1.42 -0.93 -2.99 3.22
1 Title1 0.52 3.32 -4.90 0.54
1 Title1 2.13 1.14 3.50 -0.22
...
1 TitleN 3.42 4.37 3.90 -1.26
I am trying to figure out how to do a query like can do this math:
SELECT title FROM Table2 WHERE (Table1_Row1_D0*Table2_Row1_D0)+(Table1_Row1_D1*Table2_Row1_D1)+(Table1_Row1_D2*Table2_Row1_D2) < 0.5;
However, I would like the query to iterate through the rows of Table1 and perform the SELECT against the entire Table2. Basically, I want to select the titles from Table2 where the calculation inequality is met against ALL the row combination of Table1 and Table 2.
Is this possible???
Not sure it matters, but I am using Postgre.
Basically, I want to select the titles
from Table2 where the calculation
inequality is met against ALL the row
combination of Table1 and Table 2.
For that you will want the reverse condition, where there does NOT exist an equality in Table1 for that Table2 row.
SELECT distinct title
FROM Table2
WHERE NOT EXISTS (
SELECT *
FROM Table1
WHERE (Table1.D0*Table2.D0)+(Table1.D1*Table2.D1)
+(Table1.D2*Table2.D2) >= 0.5
)
You'll want a CROSS JOIN
SELECT Table2.title
FROM Table2
CROSS JOIN Table1
WHERE (Table1.D0*Table2.D0)+(Table1.D1*Table2.D1)+(Table1.D2*Table2.D2) < 0.5;
You should be using a union. The only caveat is your returning fields from your selects must match
(SELECT * FROM Table1 WHERE conditions) UNION (SELECT * FROM Table2 WHERE conditions)
Do your checks on the script side as long as your not pulling up too much data. You also have the option to add sub selects to the where condition to limit both sides of this union query.
Related
I've a table syntax like this,
- table1
id foreign_table_id
-----------------------
1 2
2 2
3 2
4 1
5 1
6 1
The other table is,
- table2
id value
------------
1 20
2 10
I want to get a summation of table1.foreign_table_id where the data will retrieve from table2.
Like this example should produce the result 90
Please provide any solution.
Use below query.
Select sum(table2.value) as total FROM table1 LEFT JOIN table2 ON table1.foreign_table_id = table2.id
It will give u below result.
Output::
total
-----
90
SELECT SUM(table2.value) AS summation FROM table1 LEFT JOIN table2
ON table2.id = table1.foreign_table_id
I need a help with projecting my database. The purpose of this database will be to show offers in different categories. There are 1-6 categories to each item. There are around 80 categories types, so I decided to make three tables as below:
table1:
ID Item_id
1 1
2 2
3 3
4 4
5 5
table2:
ID Item_id Category
1 1 cat55
2 1 cat56
3 1 cat57
4 1 cat58
5 2 cat42
6 2 cat43
7 2 cat44
8 2 cat45
9 3 cat42
etc.
table3:
Category_id category_name
cat55 apples
cat56 oranges
cat57 bananas
cat58 pineapples
Am I doing this right? I've got a problem to make proper sql query to show my categories in php, because when I use this query:
SELECT table1.*, table2.*, table3.*
FROM table1
INNER JOIN table2
ON table1.item_id = table2.item_id
INNER JOIN table3
ON table2.category=table3.category_id
It only gives me the first category name, when I need all of them and show them like this:
Item 1: apples, oranges, bananas, pineapples
Item 2: cat42, cat43, cat44, cat45
Item 3: cat42
What am I doing wrong? Is it wrong query or I need to change the database structure to like this
table 1 and 3 unchanged
table 2:
ID Item_id c1 c2 c3 c4 c5 c6
1 1 cat55 cat56 cat57 cat58 null null
2 2 cat42 cat43 cat44 cat45 null null
3 3 cat42 null null null null null
I'm using foreach loop, so I can do only one query, I know that more queries are possible, but I need to make it as simple as possible.
If you want to fetch all names in single row for each item, following query will work:
SELECT table1.Item_Id,Group_Concat(t3.category_name separator ',') as Category_Name
FROM table1
INNER JOIN table2
ON table1.item_id = table2.item_id
INNER JOIN table3
ON table2.category=table3.category_id
Group by table1.Item_Id;
I don't find any problem in your DB Structure.
Hope it helps!
I try to select all from 2 tables in mysql database with the sum of total cost in the second table
i have a table name tbl_project contain
db_id db_projectname and other column
1 test
2 test2
3 test3
second table name tbl_activities contain
db_id db_projectname db_totalcost
1 test 200
2 test 300
3 test2 800
the out put i want is
test 500
test2 800
test3
i try this query but it didn't give me that result
select tbl_project.db_id, tbl_project.db_projectname,tbl_project.db_location,tbl_project.db_client,tbl_project.db_transferredto,tbl_project.db_psd,tbl_project.db_pdd,tbl_project.db_duration,tbl_project.db_past,tbl_project.db_padd,tbl_project.db_aduration,tbl_project.db_percent,tbl_project.db_pnote,tbl_project.db_user,tbl_project.db_cpercentage,tbl_project.db_epercentage,tbl_project.db_mpercentage,tbl_project.db_status,tbl_project.db_offer,tbl_project.db_sheet,tbl_project.db_invoice,tbl_project.db_po,sum(tbl_activities.db_totalcost) as total_cost from tbl_project,tbl_activities where
tbl_project.db_projectname=tbl_activities.db_projectname
it give me
test but sum of another project and only one project not all
You needed to use LEFT JOIN & GROUP BY
SELECT
tbl_project.db_id,
tbl_project.db_projectname,
tbl_project.db_location,
tbl_project.db_client,
tbl_project.db_transferredto,
tbl_project.db_psd,
tbl_project.db_pdd,
tbl_project.db_duration,
tbl_project.db_past,
tbl_project.db_padd,
tbl_project.db_aduration,
tbl_project.db_percent,
tbl_project.db_pnote,
tbl_project.db_user,
tbl_project.db_cpercentage,
tbl_project.db_epercentage,
tbl_project.db_mpercentage,
tbl_project.db_status,
tbl_project.db_offer,
tbl_project.db_sheet,
tbl_project.db_invoice,
tbl_project.db_po,
sum(
tbl_activities.db_totalcost
) AS total_cost
FROM
tbl_project
LEFT JOIN tbl_activities ON tbl_project.db_projectname = tbl_activities.db_projectname
GROUP BY tbl_project.db_id
Note:
Using aggregate function (e.g. SUM,COUNT..) without GROUP BY collapses the result set into a single row.
try this;
SELECT
db_projectname.db_projectname,SUM(tbl_activities.db_totalcost) AS total_cost
FROM db_projectname
LEFT JOIN tbl_activities
ON
db_projectname.db_projectname = tbl_activities.db_projectname
GROUP BY db_projectname.db_projectname
In my table 1 I have something like this
name | age
George 42
Bob 30
Ken 23
In my table 2, I have something like this, this is where i store votes for each person.
name | votes |
George 1
Ken 1
George 1
George 1
Ken 1
My goal is to combine the 2 tables, and return all the rows in table 1 even it doesn't exist in table 2.
Desire results:
name | age | total_votes
George 42 3
Bob 30 0
Ken 23 2
But instead I get:
name | age | total_votes
George 42 3
Ken 23 2
I have tried something like this
SELECT `table_1`.*, coalesce(COUNT(`table_2`.votes), 0) AS total_votes
FROM `table_1`
LEFT JOIN `table_2`
ON `table_1`.name = `table_2`.name
You can do one of these:
1) Use Right Join instead of current Left Join.
Or
2) Exchange table1 and table2 places in your join expression, like:
FROM table_2
LEFT JOIN table_1
Try this. This works in MS Access , I think this will work on your's too just convert the query to SQL:
SELECT Table1.name, First(Table1.age) AS age, Count(Table2.Votes) AS totalVotes
FROM Table1 LEFT JOIN Table2 ON Table1.name = Table2.name
GROUP BY Table1.name;
Left Join table1 to table2 so that all entry from table1 , even if its is corresponding data is null, will be included. GROUP BY your query by name so that votes will be counted by name .
I have a table that I'm querying for value 43 in the second field and I return the value of the third field
SELECT t1_field3 FROM table1 WHERE t1_field2=43
this returns 19, 39,73
t1_id t1_field2 t1_field3
----- --------- ---------
1 43 19////
2 43 39////
3 43 73////
4 73 43
5 13 40
Then I separately query a second table for additional information
SELECT * FROM table2 WHERE t2_id=t1_field3
t2_id t2_field2 t2_field3
----- --------- ---------
19 value19.2 value19.3
39 value39.2 value39.3
73 value73.2 value73.3
Is there a way I could combine both table1 and table2 in the same query?
You're describing a JOIN. In this case you don't need to explicitly use the JOIN keyword though, you can just do this:
SELECT table1.t1_field3, table2.* FROM table1, table2 WHERE table1.t1_field2=43 AND table2.t2_id = table1.t1_field3
It would probably be helpful to learn about the different types of joins at some point; Coding Horror has a good post about it
select * from table2
where t2_id in (select t1_field3 from table1 where t1_field2=43 )
There's a way to express the join directly as well like so:
select table1.t1_field3, table2.*
from table1
join table2 on table1.t1_field3 = table2.t2_id
where table1.t1_field2 = 43;