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'
Related
I know Postgres has a lot of functions, and I'm not the fittest in SQL anyways, but I need to know if its possible with Postgres to somehow get the data in a table with that statement-
SELECT table_name
FROM information_schema.tables
where table_schema='public'
I'm getting my tables I created which I want.
eg.
table_name
myTable1
myTable2
myTable3
Each of the Tables has different data filled, but every table has a column version and I want to access it.
Joining the tables wouldn't work at least it didn't went out the way I wanted. What I want is this
table_name
Version
myTable1
21
mytABLE2
12
with
Select version from mytable1 order by version desc limit 1
I get the last version but I would like to combine this somehow
I mean I can join the 3 tables but that's not what I want
So my question is it possible to do it? Or do I have to work around.
Because I believe that getting the table names is on a higher layer
In the end you need dynamic SQL for this. One way to do it, is to use a PL/pgSQL function, another way is to use query_to_xml() to run a dynamic query without the use of PL/pgSQL.
with data as (
select query_to_xml(format('select version
from %I.%I
order by version desc limit 1',
t.table_schema, t.table_name),
true, true, '') as result
from information_schema.tables t
where t.table_schema = 'public'
)
select (xpath('/row/version/text()', result))[1]::text::int as version
from data;
The format() function is used to build a SELECT query the way you need it. The query_to_xml() will then return something like:
<row xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<version>21</version>
</row>
The xpath() function is then used to extract the 21 from that XML. As it returns an array of matches, the [1] is used to extract the first match. This is then converted to an integer.
Note that if there is at least one table that does not contain a column named version this query will fail. You can work around that by extending the WHERE clause to:
where table_schema = 'public'
and exists (select *
from information_schema.columns c
where c.table_schema = t.table_schema
and c.table_name = t.table_name
and c.column_name = 'version'
On this legacy SQL Database with hundreds of tables, I need to do a inner join on all tables whose name follows a format:
barX_foo_bazX
barX_foo_bazY
barZ_foo_bazZ
I would like to inner join all tables with foo in their name
I am not sure this is possible at all.
Clearly, with this syntax it is not (but it may help understand what I'm aiming at):
USE [LegacyDB_Name]
SELECT *
FROM '%_foo_%' inner join '%_foo_%'
where my_stuff_is(some condition)
Any Suggestions? Ideas on how I can do this? Maybe there is an easier path this young padawan is not seeing...
Many Thanks!
I am not sure this is possible at all.
Nope, table names cannot contain or use wildcards, they must be strings.
My advice would be to find whatever program makes these select queries and include whatever pattern matching you need in the queries in there.
But your finished query must contain table names as strings.
Maybe the simplest way to do this is to declare a cursor based on the below query and build a dynamic sql query. Research tsql cursor and dynamic sql execution and it should be fairly simple.
SELECT *
FROM information_schema.tables
Where Table_Type = 'Base Table' And Table_Name Like '%_foo_%'
If your tables all have the same structure (i.e. columns), then you could do this in two steps.
Generate the SQL statement:
select 'UNION ALL SELECT ''' + table_name + ''' AS table_name, * FROM '
+ table_name AS stmt
from information_schema.tables
where table_type = 'BASE TABLE'
and table_catalog = 'LegacyDB_Name'
and table_name LIKE '%foo%';
The output will be something like:
stmt
--------------------------------------------------------------------
UNION ALL SELECT 'barX_foo_bazX' AS table_name, * FROM barX_foo_bazX
UNION ALL SELECT 'barX_foo_bazY' AS table_name, * FROM barX_foo_bazY
UNION ALL SELECT 'barX_foo_bazZ' AS table_name, * FROM barX_foo_bazZ
From this output, copy the SQL rows and remove the first 2 words (UNION ALL) from the first line. This is a valid SQL statement.
Execute the SQL statement derived above
If you need this SQL more often, then create a view for it:
CREATE OR REPLACE VIEW all_foo AS
SELECT 'barX_foo_bazX' AS table_name, * FROM barX_foo_bazX
UNION ALL SELECT 'barX_foo_bazY' AS table_name, * FROM barX_foo_bazY
UNION ALL SELECT 'barX_foo_bazZ' AS table_name, * FROM barX_foo_bazZ;
Now you can query like
SELECT * FROM all_foo WHERE ...
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
I have a list of column names of all the views in a excel scheet. How to find what all columns for these views relating to dbo schema have the value -1 in place of null?
basically I understand we must use a cross product between the column names in excel and the views in db to get the columns that views are using. for that my query looks like this
SELECT TABLE_NAME as [View Name]
FROM INFORMATION_SCHEMA.VIEWS
WHERE table_schema = 'dbo' and
VIEW_DEFINITION LIKE '%DimCurrencyId%'
UNION
SELECT TABLE_NAME as [View Name]
FROM INFORMATION_SCHEMA.VIEWS
WHERE table_schema = 'dbo' and
VIEW_DEFINITION LIKE '%DimTimeZoneId%'
UNION
.........
I want to improve this query result to show the columns of the views as well and show which of them are given -1 in place of null Group by the view name.
My result should look like
viewName ColumnName
xxxx xxxx
xxxx xxxx
Guys is there any other way to determine a table exists other than below
select count(*) from <table> where rownum =1
select * from user_table where table_name=<table>
kindly let me know the best way to check whether a table exists using oracle sql.
Thanks for the answer , my requirement is to check from the first date of current month ie 01/12/2010 with table name in the format suresh_20101201 exists in the database, if not then it should check for table suresh_20101202 and thereon till suresh_20101231 . is it possible to do in oracle sql query.
You can do this (in oracle, in mssql there is a bit different):
select count(*)
from all_objects
where object_type in ('TABLE','VIEW')
and object_name = 'your_table_name';
In most sql servers there is a system domain where you can query for a table's existence. It's highly implementation specific though. For example, in recent versions of MySql:
SELECT table_name FROM INFORMATION_SCHEMA.TABLES
WHERE table_schema = 'db_name'
AND table_name LIKE 'whatever'
You need to ask your server's system catalog. Not sure what database you meant but for SQL Server it would be:
select * from sys.tables where name='your-table-name-'
Used this in Oracle SQL Developer:
SELECT COUNT(*) FROM DUAL WHERE EXISTS (
SELECT * FROM ALL_OBJECTS WHERE OBJECT_TYPE = 'TABLE' AND OWNER = 'myschema' AND OBJECT_NAME = 'your_table_name')
This will return either a 0 or 1 if your table exists or not in the ALL_OBJECTS records.
Below query can be triggered to Oracle for checking whether any Table present in DB or not:
SELECT count(*) count FROM dba_tables where table_name = 'TABLE_NAME'
Above query will return count 1 if table 'TABLE_NAME' is present in Database
Look in the schema, might event be able to use sys.objects and check for a type at the same time.....
Something like