I want to access some table like Toyota_Corolla, Toyota_Camry, Toyota_Prius, Toyota_Rav4
Instead of typing out multiple SELECT statements like the following:
SELECT * FROM Toyota_Corolla;
SELECT * FROM Toyota_Camry;
SELECT * FROM Toyota_Prius;
SELECT * FROM Toyota_Rav4;
Is there a way to create a list of strings like ['Corolla', 'Camry', 'Prius', Rav4'] and iterate through the list after the FROM line to something similar to:
SELECT * FROM 'Toyota_'` + 'some loop to iterate the list of car model'
I know for my example, it's easier to just type out the whole thing, but what about the situation when Toyota has hundred of models?
This is MS SQL Server DBMS
No. First, you should fix your data model so you have a single table with an additional column for the Toyota model. That is the right way to store the data.
With the data you have, you can emulate this with a view:
create view vw_toyota as
select 'Corolla' as toyota_model, t.* from Toyota_Corolla t union all
select 'Camry' as toyota_model, t.* from Toyota_Camry t union all
select 'Prius' as toyota_model, t.* from Toyota_Prius t union all
select 'Rav4' as toyota_model, t.* from Toyota_Rav4 t;
This also adds the source table information.
And then do:
select *
from vw_toyota;
Related
I have this huge table upon which I apply a lot of processing (using CTEs), and I want to perform a UNION ALL on 2 particular CTEs.
SELECT *
, 0 AS orders
, 0 AS revenue
, 0 AS units
FROM secondary_prep_cte WHERE purchase_event_flag IS FALSE
UNION ALL
SELECT *
FROM results_orders_and_revenues_cte
I get a "Column 1164 in UNION ALL has incompatible types : STRING,DATE at [97:5]
Obviously I don't know the name of the column, and I'd like to debug this but I feel like I'm going to waste a lot of time if I can't pin-point which column is 1164.
I also think this is a problem of the order of columns between the CTEs, so I have 2 questions:
How do I identify the 1164th column
How do I order my columns before performing the UNION ALL
I found this similar question but it is for MSSQL, I am using BigQuery
You can get information from INFORMATION_SCHEMA.COLUMNS but you'll need to create a table or view from the CTE:
CREATE OR REPLACE VIEW `project.dataset.secondary_prep_view` as select * from (select 1 as id, "a" as name, "b" as value)
Then:
SELECT * FROM dataset.INFORMATION_SCHEMA.COLUMNS WHERE table_name = 'secondary_prep_view';
I have one mapping table, let us say VW_MAPPING.
VW_MAPPING has columns and data like this:
MetricTable
A VW_A
B VW_B
C VW_C
D VW_D
E VW_E
Now I want to perform a conditional SELECT.
Like
when Metric = A then SELECT * FROM VW_A;
when Metric = B then SELECT * FROM VW_B;
i) All the tables have the same number of columns.
ii)The underlying tables don't have the metric column
Basically I will get the Metric value from an Input Form. So I want to show the data accordingly. If A is given then I will show data from VW_A. And for which response we have to use which table that we will get from VW_MAPPING.
What I want is something like this :
SELECT * FROM variable_table_name;
variable_table_name = SELECT TABLE FROM VW_MAPPING WHERE METRIC = form input
This is the pseudo code
I cannot use PL/SQL.
Although probably not the most efficient way, I would be inclined to do:
with v as (
select 'A' as metric, a.* from vw_a a union all
select 'B', b.* from vw_b b union all
select 'C', c.* from vw_c c union all
. . .
)
select v.*
from v
where metric = :metric;
That is, the mapping table is not actually useful. Instead of a mapping table, you should have one table with all the metrics and an additional column that identifies the metric. You can also do this using a view instead of a table.
Is this what are you expecting?
SELECT * FROM VW_A where Metric in
(selct Metric from VW_MAPPING);
SELECT * FROM VW_B where Metric in
(selct Metric from VW_MAPPING);
There are a few ways of doing this.
By far the best is to handle this in the user interface layer - the code behind your input form should decide which query to execute. This has a number of benefits: the code is much simpler, it will probably be faster, and your database does the "storing and modifying data" task, not the "react to user choices" task.
If you really can't do that, you can use a UNION
select *
from VW_A
where metric = 'A'
union
select *
from VW_A
where metric = 'B'
...
This embeds the decision in your query, rather than looking at your mapping table.
If you really want to use your mapping table, you'll need to use dynamic SQL, but you say that you can't use PL/SQL.
I'm not aware of any other options.
How can I abbreviate a list so that
WHERE id IN ('8893171511',
'8891227609',
'8884577292',
'886790275X',
.
.
.)
becomes
WHERE id IN (name of a group/list)
The list really would have to appear somewhere. From the point of view of your code being maintainable and reusable, you could represent the list in a CTE:
WITH id_list AS (
SELECT '8893171511' AS id UNION ALL
SELECT '8891227609' UNION ALL
SELECT '8884577292' UNION ALL
SELECT '886790275X'
)
SELECT *
FROM yourTable
WHERE id IN (SELECT id FROM cte);
If you have a persistent need to do this, then maybe the CTE should become a bona fide table somewhere in your database.
Edit: Using the Horse's suggestion, we can tidy up the CTE to the following:
WITH id_list (id) AS (
VALUES
('8893171511'),
('8891227609'),
('8884577292'),
('886790275X')
)
If the list is large, I would create a temporary table and store the list there.
That way you can ANALYZE the temporary table and get accurate estimates.
The temp table and CTE answers suggested will do.
Just wanted to bring another approach, that will work if you use PGAdmin for querying (not sure about workbench) and represent your data in a "stringy" way.
set setting.my_ids = '8893171511,8891227609';
select current_setting('setting.my_ids');
drop table if exists t;
create table t ( x text);
insert into t select 'some value';
insert into t select '8891227609';
select *
from t
where x = any( string_to_array(current_setting('setting.my_ids'), ',')::text[]);
In Oracle, is there a way to query the same, structurally identical table out of multiple schema within the same database in single line? Obviously assuming the user has permissions to access all schema, I could build a query like:
select * from schema1.SomeTable
union all
select * from schema2.SomeTable
But is it possible, given the right permissions to say something like:
select * from allSchema.SomeTable
...and bring back all rows for all the schema? And related to this, is it possible to pick which schema, such as:
select * from allSchema.SomeTable where schemaName in ('schema1','schema2')
The simplest option, as far as I can tell, is to create a VIEW (as UNION of all tables across all those users), and then SELECT FROM VIEW.
For example:
create or replace view my_view as
select 'schema_1' source_schema, id, name from schema_1.table union
select 'schema_2' source_schema, id, name from schema_2.table union
...
-- select all
select * from my_view;
-- select all that belongs to one of schemas
select * from my_view where source_schema = 'schema_1';
I've been playing around with the sample on Jeff' Server blog to compare two tables to find the differences.
In my case the tables are a backup and the current data. I can get what I want with this SQL statement (simplified by removing most of the columns). I can then see the rows from each table that don't have an exact match and I can see from which table they come.
SELECT
MIN(TableName) as TableName
,[strCustomer]
,[strAddress1]
,[strCity]
,[strPostalCode]
FROM
(SELECT
'Old' as TableName
,[JAS001].[dbo].[AR_CustomerAddresses].[strCustomer]
,[JAS001].[dbo].[AR_CustomerAddresses].[strAddress1]
,[JAS001].[dbo].[AR_CustomerAddresses].[strCity]
,[JAS001].[dbo].[AR_CustomerAddresses].[strPostalCode]
FROM
[JAS001].[dbo].[AR_CustomerAddresses]
UNION ALL
SELECT
'New' as TableName
,[JAS001new].[dbo].[AR_CustomerAddresses].[strCustomer]
,[JAS001new].[dbo].[AR_CustomerAddresses].[strAddress1]
,[JAS001new].[dbo].[AR_CustomerAddresses].[strCity]
,[JAS001new].[dbo].[AR_CustomerAddresses].[strPostalCode]
FROM
[JAS001new].[dbo].[AR_CustomerAddresses]) tmp
GROUP BY
[strCustomer]
,[strAddress1]
,[strCity]
,[strPostalCode]
HAVING
COUNT(*) = 1
This Stack Overflow Answer gives me a much cleaner SQL query but does not tell me from which table the rows come.
SELECT * FROM [JAS001new].[dbo].[AR_CustomerAddresses]
UNION
SELECT * FROM [JAS001].[dbo].[AR_CustomerAddresses]
EXCEPT
SELECT * FROM [JAS001new].[dbo].[AR_CustomerAddresses]
INTERSECT
SELECT * FROM [JAS001].[dbo].[AR_CustomerAddresses]
I could use the first version but I have many tables that I need to compare and I think that there has to be an easy way to add the source table column to the second query. I've tried several things and googled to no avail. I suspect that maybe I'm just not searching for the correct thing since I'm sure it's been answered before.
Maybe I'm going down the wrong trail and there is a better way to compare the databases?
Could you use the following setup to accomplish your goal?
SELECT 'New not in Old' Descriptor, *
FROM
(
SELECT * FROM [JAS001new].[dbo].[AR_CustomerAddresses]
EXCEPT
SELECT * FROM [JAS001].[dbo].[AR_CustomerAddresses]
) a
UNION
SELECT 'Old not in New' Descriptor, *
FROM
(
SELECT * FROM [JAS001].[dbo].[AR_CustomerAddresses]
EXCEPT
SELECT * FROM [JAS001new].[dbo].[AR_CustomerAddresses]
) b
You can't add the table name there because union, except, and intersection all compare all columns. This means you can't differentiate between them by adding the table name to the query. A group by gives you control over what columns are considered in finding duplicates so you can exclude the table name.
To help you with the large number of tables you need to compare you could write a sql query off the metadata tables that hold table names and columns and generate the sql commands dynamically off those values.
Derive one column using table names like below
SELECT MIN(TableName) as TableName
,[strCustomer]
,[strAddress1]
,[strCity]
,[strPostalCode]
,table_name_came
FROM
(SELECT 'Old' as TableName
,[JAS001].[dbo].[AR_CustomerAddresses].[strCustomer]
,[JAS001].[dbo].[AR_CustomerAddresses].[strAddress1]
,[JAS001].[dbo].[AR_CustomerAddresses].[strCity]
,[JAS001].[dbo].[AR_CustomerAddresses].[strPostalCode]
,'[JAS001].[dbo].[AR_CustomerAddresses]' as table_name_came
FROM [JAS001].[dbo].[AR_CustomerAddresses]
UNION ALL
SELECT 'New' as TableName
,[JAS001new].[dbo].[AR_CustomerAddresses].[strCustomer]
,[JAS001new].[dbo].[AR_CustomerAddresses].[strAddress1]
,[JAS001new].[dbo].[AR_CustomerAddresses].[strCity]
,[JAS001new].[dbo].[AR_CustomerAddresses].[strPostalCode]
,'[JAS001new].[dbo].[AR_CustomerAddresses]' as table_name_came
FROM [JAS001new].[dbo].[AR_CustomerAddresses]
) tmp
GROUP BY [strCustomer]
,[strAddress1]
,[strCity]
,[strPostalCode]
,table_name_came
HAVING COUNT(*) = 1