System is HP VERTICA 7.1
I am trying to create a SQL query which will dynamically find all particular tables in a specific schema that have a Timestamp column named DWH_CREATE_TIMESTAMP from system tables. (I have completed this part successfully)
Then, pass this list of tables to an outer query or some kind of looping statement which will select the MAX(DWH_CREATE_TIMESTAMP) and TABLE_NAME from all the tables in the list (200+) and union all the results together into one list.
The expected output is a 2 column table with all said tables with that TS field and the max of each value. Tables are constantly being created and dropped, so the point is to make everything totally dynamic where no TABLE_NAME values are ever hard-coded.
Any idea of Vertica specific ways to accomplish this without UDF's would be greatly appreciated.
Inner Query (working):
select distinct(table_name)
from columns
where column_name = 'DWH_CREATE_TIMESTAMP'
and table_name in (select DISTINCT(table_name) from all_tables where schema_name = 'PTG_DWH')
Outer Query (attempted - not working):
SELECT Max(DWH_CREATE_DATE) from
WITH table_name AS (
select distinct(table_name)
from columns
where column_name = 'DWH_CREATE_DATE' and table_name in (select DISTINCT(table_name) from all_tables where schema_name = 'PTG_DWH'))
SELECT MAX(DWH_CREATE_DATE)
FROM table_name
Thanks!!!
No way to do that in one SQL .
You can used the below method for node max timestamp columns values
select projections.anchor_table_name,vs_ros.colname,max(max_value) from vs_ros,vs_ros_min_max_values,storage_containers,projections where vs_ros.colname ilike 'timestamp'
and vs_ros.salstorageid=storage_containers.sal_storage_id
and vs_ros_min_max_values.rosid=vs_ros.rosid
and storage_containers.projection_name=projections.projection_name
group by projections.anchor_table_name,vs_ros.colname
Related
In Snowflake, I retrieve different views with the following SQL query:
SELECT * FROM "myDatabase"."mySchema"."VIEWS"
That returns a table with these columns notably:
TABLE_ID
TABLE_NAME
TABLE_SCHEMA_ID
TABLE_SCHEMA
TABLE_CATALOG_ID
TABLE_CATALOG
TABLE_OWNER
VIEW_DEFINITION
For each VIEW_DEFINITION column entries, I am trying to extract all the strings <Schema_Name>.<View_Name> (or at least the <Schema_Name>).
Is it possible to do that with a SQL query (or by any other way)?
Edit
The table I obtain using the initial query is as follows:
TABLE_ID
TABLE_NAME
TABLE_SCHEMA_ID
TABLE_SCHEMA
TABLE_CATALOG_ID
TABLE_CATALOG
TABLE_OWNER
VIEW_DEFINITION
0001
MY_TABLE_NAME
99
MY_TABLE_SCHEMA
20
PMY_TABLE_CATALOG
MY_OWNER_VIEWS_ADMIN
…
where the VIEW_DEFINITION column contains queries like the one below:
"CREATE OR REPLACE VIEW My_Table_Schema_VIEWS.My_Table_Name AS
WITH STUDY_SITE_SCOPE AS (
SELECT
...
FROM (
SELECT
A.SUBJECT_NUMBER
, A.SUBJECT_STATUS
FROM <Schema_Name>.<View_Name_1> X
JOIN <Schema_Name>.<View_Name_2> Y
...
)
JOIN (
SELECT
...
FROM <Schema_Name>.<View_Name_3> X
JOIN <Schema_Name>.<View_Name_4> Y
...
)
..."
From this VIEW_DEFINITION I am trying to extract all the <Schema_Name>.<View_Name_XX> strings (or at least the <Schema_Name>).
I assume you want to get all base schemas your current view is built on top of.
To answer your question short: Yes, it is.
Maybe the following procedure is giving you an idea on how to solve it via SQL or a Stored Procedure:
Query the view definition
Search for all strings within the view definition that follow the "FROM" or "JOIN" clause
Extract them and probably check for the database name in front of the schema name
You can use information_schema.tables:
select t.*
from information_schema.tables t
where t.table_type = 'VIEW'
I got an error while creating an empty table by joining two tables.
I have two tables tab1 & tab2 and there are many common columns names in both tables.
I tried this:
create table tab3 as
select * from tab1 a, tab2 b where a.id = b.id and 1=2;
This gave ORA-00957: duplicate column name. As I mentioned above there are many common columns name between these two tables. If I prepare a create table statement by writing around 500 column names one by one then it will consume lots of time. Please help me out here.
The simple answer is, don't use *. Or is that the whole point, to avoid writing five lines of column names?
One way to avoid these conflicts, but that assumes that you are joining on all columns with the same name in both tables and on no other columns, is to do something like
create table new_table as
select *
from table_a natural join table_b
where null is not null
;
(As you can guess, as an aside, I prefer null is not null to 1 = 2; the parser seems to prefer it too, as it will rewrite 1 = 2 as null is not null anyway.)
Will you need to control the order of the columns in the new table? If you do, you will need to write them out completely in the select clause, regardless of which join syntax you choose to use.
That's an interesting question.
The only idea I have to offer it to let another query to compose the query you need
select 'select ' || listagg(col_name, ', ') within group(order by 1) || 'from tab1 a,tab2 b where (a.id=b.id) and 1=2'
from (select 'a.' || column_name col_name from user_tab_cols where table_name = 'TAB1'
union all
select 'b.' || column_name from user_tab_cols where table_name = 'TAB2')
Please be aware for subqueries you need to specify table names in the upper case
I'm trying to query two information_schema tables in PostgreSQL - tables and columns in order to get the following result:
table_name - columns_as_json_array
Sort of converting this one to many relation into a json array column.
I tried a lot of different methods and came up with somethings like this:
SELECT t.table_name, c.json_columns
FROM information_schema.TABLES t
LEFT JOIN LATERAL(
SELECT table_name, json_agg(row_to_json(tbc)) AS json_columns
FROM information_schema.COLUMNS tbc
WHERE t.table_name = tbc.table_name
GROUP BY table_name
) as c ON TRUE;
This results a list of table_names but the json_columns always contains all of the columns available instead of the columns of that certain table.
Any ideas?
I don't really see the point for a lateral join here. As far as concerns, you can get the expected results by aggregating information_schema.columns:
select table_name, json_agg(row_to_json(c)) json_columns
from information_schema.columns c
group by table_name
order by table_name
My question is, is it possible to list all the columns from the whole database not just in specific tables based on 3 different criteria which ones are in an "OR" relationship. so for example I have database called "Bank" and I have 3 criterias "Criteria1; Criteria2; Criteria3" and if any of them is true so the relation between them should be OR and not AND than I will get back all the columns matching the criterias and the output put should provide "account_id" or "customer_id" from the same table.
How do I procced in this case?
It is possible, but you probably don't want to do it. Anyway, you could write a stored procedure that finds all tables that contain the columns you want:
select distinct table_name from user_tab_cols utc
where exists (select * from user_tab_cols where table_name = utc.table_name
and column_name = 'ACCOUNT_ID')
and exists (select * from user_tab_cols where table_name = utc.table_name
and column_name = 'CUSTOMER_ID');
Given the tables you could run a query where you append table name and your criteria:
execute immediate 'select account_id, customer_id from agreement where '
|| your_criteria_here;
A bit messy, inefficient and treat this as pseudo-code. However, if you really want to do this for an ad-hoq query it should point you in the right direction!
I have an Oracle database with many tables that have identical structure (columns are all the same). The table names are similar also. The names of the tables are like table_1, table_2, table_3...
I know this isn't the most efficient design, but I don't have the option of changing this at this time.
In this case, is it possible to make a single sql query, to extract all rows with the same condition across multiple tables (hundreds of tables) without explicitly using the exact table name?
I realize I could use something like
select * from table_1 UNION select * from table_2 UNION select * from table_3...select * from table_1000
But is there a more elegant sql statement that can be run that extracts from all matching table names into one result without having to name each table explicitly.
Something like
select * from table_%
Is something like that possible? If not, what is the most efficient way to write this query?
You can use dbms_xmlgen to query tables using a pattern, which generates an XML document as a CLOB:
select dbms_xmlgen.getxml('select * from ' || table_name
|| ' where some_col like ''%Test%''') as xml_clob
from user_tables
where table_name like 'TABLE_%';
You said you wanted a condition, so I've included a dummy one, where some_col like '%Test%'.
You can then use XMLTable to extract the values back as relational data, converting the CLOB to XMLType on the way:
select x.*
from (
select xmltype(dbms_xmlgen.getxml('select * from ' || table_name
|| ' where some_col like ''%Test%''')) as xml
from user_tables
where table_name like 'TABLE_%'
) t
cross join xmltable('/ROWSET/ROW'
passing t.xml
columns id number path 'ID',
some_col varchar2(10) path 'SOME_COL'
) x;
SQL Fiddle demo which retrieves one matching row from each of two similar tables. Of course, this assumes your table names follow a useful pattern like table_%, but you suggest they do.
This is the only way I know to do something like this without resorting to PL/SQL (and having searched back a bit, was probably inspired by this answer to count multiple tables). Whether it's efficient (enough) is something you'd need to test with your data.
This is kind of messy and best performed in a middle-tier, but I suppose you could basically loop over the tables and use EXECUTE IMMEDIATE to do it.
Something like:
for t in (select table_name from all_tables where table_name like 'table_%') loop
execute immediate 'select blah from ' || t.table_name;
end loop;
You can write "select * from table_1 and table_2 and tabl_3;"