How do I write this SQL into Rails? - sql

I want to get the sequence for the id column in the tags table as
SELECT pg_get_serial_sequence(‘tags’, ‘id’);
And then I want to use the result from the above Query (the sequence) as an input to the second query. Let s say the first query is called sequence
I want to perform the second query as:
SELECT setval(**sequence**, SELECT max(id) FROM tags);
Any idea on how to do this ?

You can use ActiveRecord::Base.connection.execute("your SQL query here").

Related

Get the list of result from first sql query and execute second query on the result of list of first query

So, I am working with redshift and SQL for the first time. I have run into this problem due to my limted knowledge of SQL.
I have this first query which return me tables with the columnA. (TableX, TableY... etc)
SELECT tablename
FROM PG_TABLE_DEF
WHERE ("column" = 'columnA');
Also I have this second query which returns me all the rows from the table containig certain value of columnA.
SELECT *
FROM TableX
WHERE columnA='123934'
What I want to achieve is take the result from the first query which is list of tables, and for each table run the second query i.e. get the rows with value of columnA=123934 for each table returned from first query.
What you want to achieve is done using dynamic SQL. Dynamic queries let you run a query from a string.
I am not an Redshit user but to generate the SQL string you need to run you could use the following query:
SELECT 'SELECT * FROM '||tablename ||' WHERE ColumnA= ''123934''; '
FROM PG_TABLE_DEF
WHERE ("column" = 'columnA');
You can try running it manually.

Select name from system table and select from this table

I need dynamically obtain table name from system table and perform a select query on this table example:
SELECT "schema"+'.'+"table" FROM SVV_TABLE_INFO WHERE "table" LIKE '%blabla%'
it returns my_schema.the_main_blabla_table
And after I get this table name I need to perform :
SELECT * FROM my_schema.the_main_blabla_table LIMIT 100
Is it possible to in a single query?
If you are talking about select subquery after "from" i can say that you can do this.
You will get something like this:
SELECT * FROM
(
SELECT "schema"+'.'+"table" FROM SVV_TABLE_INFO WHERE "table" LIKE '%blabla%'
)
LIMIT 100
Unfortunately, i can't test it on yor data, but i very interested in result because i have never done something like this. If i get your question incorrect, tell me pls.
Amazon Redshift does not support the ability to take the output of a query and use it as part of another query.
Your application will need to query Redshift to obtain the relevant table name(s), then make another call to Redshift to query that table.

How do I select a value in a key:value pair within a list in a column using SQL?

In a table called payouts, there is a column stripeResponseData where the data is in the following structure:
{"id":"tr_1BlSHbGQXLV7RqqnHJffUVO0","object":"transfer","amount":39415,"amount_reversed":0,"balance_transaction":"txn_1BlSHbGQXfV7AqqnGi2o7UiY","created":1516239215,"currency":"usd","description":null,"destination":"acct_1BWWAmAzms5xPfV9","destination_payment":"py_1BlSHbAzms5xkfV91RHAOrno","livemode":true,"metadata":{},"reversals":{"object":"list","data":[],"has_more":false,"total_count":0,"url":"/v1/transfers/tr_1BlSHbYQXLV7AqqnHJffUVO0/reversals"},"reversed":false,"source_transaction":null,"source_type":"card","transfer_group":null}
Within my SQL SELECT statement, I want to return only the value of the key "destination". How do I write my SQL query?
My desired result of the query:
SELECT "stripeResponseData" FROM payouts [...]
(where I don't know how to write [...]) should look like the following (assume we have 3 rows with different values on "destination"):
acct_1BWWAmAzms5xPfV9
acct_1AY0phDc9pCDpLR8
acct_1AwG3VL7DXxftOaS
How do I extract that value from the list within the stripeResponseData column?
See this sqlfiddle. This query will fetch the ID from stripResponseData where the id is a specific id (Probably not very useful, but does show you how to select and query):
SELECT data->>'id' FROM stripeResponseData WHERE data #> '{"id":"tr_1BlSHbGQXLV7RqqnHJffUVO0"}';
Because you mentioned your data was a string, you need to to type conversions to query/use it correctly. See this sqlfiddle:
SELECT data::jsonb->>'id' FROM stripeResponseData WHERE data::jsonb #> '{"id":"tr_1BlSHbGQXLV7RqqnHJffUVO0"}';
Per your edit, you can simply query destination in almost the exact same way. This will get all the id's from stripeResponseData where destination = acct_1BWWAmAzms5xPfV9:
SELECT data::jsonb->>'id' FROM stripeResponseData WHERE data::jsonb #> '{"destination":"acct_1BWWAmAzms5xPfV9"}';

select single value into multi rows oracle sql

I want to select one value and retrieve it into multi rows i tried to search about this case but i didn't find the write way to sole it and
and finaly sorry for my English
try select your_value, t.* from table t

Inserting a new column into SQL

I have these queries:
SELECT *
FROM dbo.GRAUD_ProjectsByCostCategory
select right(CostCategoryId,14) as CostBreak
from dbo.GRAUD_ProjectsByCostCategory
They work well in that they give me the correct data, but I would like to know how to combine the new column CostBreak into the table of results rather than as a separate query result.
An example of the results I get are as below:
Where I want them in the same table
The data is coming from the same table so you should be able to just add that value to your initial query. You do not even have to perform a join to get it:
SELECT name,
description,
project,
CostCategoryId,
right(CostCategoryId,14) as CostBreak
FROM dbo.GRAUD_ProjectsByCostCategory