How to include table name in result for wildcard query? - google-cloud-platform

I'm querying from a bunch of tables in bigquery using a wildcard query. I'd like each result row to show which table it's from.
I've tried to include _TABLE_SUFFIX in the select, but it won't compile:
SELECT _TABLE_SUFFIX, *
FROM `foo.bar_*`
WHERE x = ...
Invalid field name "_TABLE_SUFFIX"

use alias as in below example
SELECT _TABLE_SUFFIX as table_name, *
FROM `foo.bar_*`
WHERE x = ...
You can also use below to preserve full table name
SELECT CONCAT('bar_', _TABLE_SUFFIX) as table_name, *
FROM `foo.bar_*`
WHERE x = ...
Note also: Field names are not allowed to start with the (case-insensitive) prefixes _PARTITION, _TABLE_, _FILE_ and _ROW_TIMESTAMP

Related

How to excldue null values using REGEXP_SUBSTR

The following statement retrieve the value of sub tag msg_id from MISC column if the sub stag contain value like %PACS%.
SELECT REGEXP_SUBSTR(MISC, '(^|\s|;)msg_id = (.*?)\s*(;|$)',1,1,NULL,2) AS TRANS_REF FROM MISC_HEADER
WHERE MISC LIKE '%PACS%';
I notice the query return record with null value (without msg_id) as well. Any idea if can exclude those null records from the syntax of REGEXP_SUBSTR, without adding any where clause.
Sample data of MISC:
channel=atm ; phone=0123 ; msg_id=PACS00812 ; ustrd=U123
channel=pos; phone=9922; ustrd=U156
The second record without msg_id, so it need to be excluded.
This method does not use REGEXP so may not be suitable for you.
However, it does satisfy your requirement.
This takes your embedded list of msg_id, breaks it out to a row for each component for an ID (I've assumed you do have something uniquely identifies each record).
It then only returns the original row where one of the rows for the ID has 'PACS' in it.
WITH thedata
AS (SELECT 1 AS theid
, 'channel=atm ; phone=0123 ; msg_id=PACS00812 ; ustrd=U123'
AS msg_id
FROM DUAL
UNION ALL
SELECT 2, 'channel=pos; phone=9922; ustrd=U156' FROM DUAL)
, mylist
AS (SELECT theid, COLUMN_VALUE AS msg_component
FROM thedata
, XMLTABLE(('"' || REPLACE(msg_id, ';', '","') || '"')))
SELECT *
FROM thedata td
WHERE EXISTS
(SELECT 1
FROM mylist m
WHERE m.theid = td.theid
AND m.msg_component LIKE '%PACS%')
Thedata sub-query is simply to generate a couple of records and pretend to be your table. You could remove that and substitute your actual table name.
There are other ways to break up an embedded list including ones that use REGEXP, I just find the XMLTABLE method 'cleaner'.

How do you query table names and row counts for all tables in a schema using HP NonStop SQL/MX?

How do you query table names and row counts for all tables in a schema using HP NonStop SQL/MX?
Thanks!
This might help you, althought this is more standard SQL and im not sure how much variation comes into sqlmx
SELECT
TableName = t.NAME,
TableSchema = s.Name,
RowCounts = p.rows
FROM
sys.tables t
INNER JOIN
sys.schemas s ON t.schema_id = s.schema_id
INNER JOIN
sys.indexes i ON t.OBJECT_ID = i.object_id
INNER JOIN
sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id
WHERE
t.is_ms_shipped = 0
GROUP BY
t.NAME, s.Name, p.Rows
ORDER BY
s.Name, t.Name
Obviously this is an example, replace example data and table info with yours
Here is how to list the tables in a sql/mx schema, note that the system catalog name given here is an example, replace NONSTOP_SQLMX_SYSNAME with NONSTOP_SQLMX_xxxx where xxxx is the Expand node name of your system.
Also the definition schema name includes the schema version number, this example uses 3600. This example lists all the base table names in schema JDFCAT.T.
See chapter 10 of the SQL/MX reference manual for information on the metadata tables.
The table row counts are not stored in the system metadata, so you can't get them from there. For a table do SELECT ROW COUNT FROM TABLE;
SELECT
O.OBJECT_NAME
FROM
NONSTOP_SQLMX_SYSNAME.SYSTEM_SCHEMA.CATSYS C
INNER JOIN NONSTOP_SQLMX_SYSNAME.SYSTEM_SCHEMA.SCHEMATA S
ON (S.CAT_UID = C.CAT_UID)
INNER JOIN JDFCAT.DEFINITION_SCHEMA_VERSION_3600.OBJECTS O
on S.SCHEMA_UID = o.SCHEMA_UID
WHERE C.CAT_NAME = 'JDFCAT' AND
S.SCHEMA_NAME = 'T' AND
O.OBJECT_TYPE = 'BT'
READ UNCOMMITTED ACCESS;

SQL String error? No Such Column

I'm using sqlite3 in my c++ program and am trying to run an SQL string in the
sqlite3_get_table function.
Here's my sql string.
SELECT name FROM sqlite_master WHERE type='table' AND name=test_table;
I keep getting the error "no such column "test_table"" .
All I am trying to do is confirm the existence of a table in my database. That's all.
Any clues as to what's wrong with my string.
In SQLite double quotes ('"') is the identifier-escape character, so assuming this is your SQL (raw SQL, nothing to do with C++):
SELECT
name
FROM
sqlite_master
WHERE
type = 'table'
AND
name = "test_table;"
Is equivalent to:
...
name = test_table
...which obviously isn't what you want.
You should use single-quoted strings in SQL, and the statement-terminating semicolon should go at the very end:
SELECT
name
FROM
sqlite_master
WHERE
type = 'table'
AND
name = 'test_table';

SqlAlchemy core union_all not adding parentheses

I have the following sample code:
queries = []
q1 = select([columns]).where(table.c.id == #).limit(#)
queries.append(q1)
q2 = select([columns]).where(table.c.id == #).limit(#)
queries.append(q2)
final_query = union_all(*queries)
The generated SQL should be this:
(select columns from table where id = # limit #)
UNION ALL
(select columns from table where id = # limit #)
But, I'm getting
select columns from table where id = # limit #
UNION ALL
select columns from table where id = # limit #
I tried using subquery, as follows for my queries:
q1 = subquery(select([columns]).where(table.c.id == #).limit(#))
The generated query then looks like this:
SELECT UNION ALL SELECT UNION ALL
I also tried doing
q1 = select([columns]).where(table.c.id == #).limit(#)).subquery()
But, I get the error:
'Select' object has no attribute 'subquery'
Any help to get the desired output with my subqueries wrapped in parentheses?
Note: this is not a duplicate of this question, because I'm not using Session.
EDIT
Okay, this works, but I don't believe it is very efficient, and it's adding an extra select * from (my sub query), but it works.
q1 = select('*').select_from((select(columns).where(table.c.id == #).limit(#)).alias('q1'))
So, if anyone has any ideas to optimize, or let me know if this is as good as it gets. I would appreciate it.
The author of SQLAlchemy seems to be aware of this and mentions a workaround for it on the SQLAlchemy 1.1 changelog page. The general idea is to do .alias().select() on each select.
stmt1 = select([table1.c.x]).order_by(table1.c.y).limit(1).alias().select()
stmt2 = select([table2.c.x]).order_by(table2.c.y).limit(2).alias().select()
stmt = union(stmt1, stmt2)

Show tables, describe tables equivalent in redshift

I'm new to aws, can anyone tell me what are redshifts' equivalents to mysql commands?
show tables -- redshift command
describe table_name -- redshift command
All the information can be found in a PG_TABLE_DEF table, documentation.
Listing all tables in a public schema (default) - show tables equivalent:
SELECT DISTINCT tablename
FROM pg_table_def
WHERE schemaname = 'public'
ORDER BY tablename;
Description of all the columns from a table called table_name - describe table equivalent:
SELECT *
FROM pg_table_def
WHERE tablename = 'table_name'
AND schemaname = 'public';
Update:
As pointed by #Kishan Pandey 's answer, if you are looking for details of a schema different by public, you need to set search_path to my_schema. (show search_path display current search path)
Listing tables in my_schema schema:
set search_path to my_schema;
select * from pg_table_def;
I had to select from the information schema to get details of my tables and columns; in case it helps anyone:
SELECT * FROM information_schema.tables
WHERE table_schema = 'myschema';
SELECT * FROM information_schema.columns
WHERE table_schema = 'myschema' AND table_name = 'mytable';
Or simply:
\dt to show tables
\d+ <table name> to describe a table
Edit: Works using the psql command line client
Tomasz Tybulewicz answer is good way to go.
SELECT * FROM pg_table_def WHERE tablename = 'YOUR_TABLE_NAME' AND schemaname = 'YOUR_SCHEMA_NAME';
If schema name is not defined in search path , that query will show empty result.
Please first check search path by below code.
SHOW SEARCH_PATH
If schema name is not defined in search path , you can reset search path.
SET SEARCH_PATH to '$user', public, YOUR_SCEHMA_NAME
You can use - desc / to see the view/table definition in Redshift. I have been using Workbench/J as a SQL client for Redshift and it gives the definition in the Messages tab adjacent to Result tab.
In the following post, I documented queries to retrieve TABLE and COLUMN comments from Redshift.
https://sqlsylvia.wordpress.com/2017/04/29/redshift-comment-views-documenting-data/
Enjoy!
Table Comments
SELECT n.nspname AS schema_name
, pg_get_userbyid(c.relowner) AS table_owner
, c.relname AS table_name
, CASE WHEN c.relkind = 'v' THEN 'view' ELSE 'table' END
AS table_type
, d.description AS table_description
FROM pg_class As c
LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
LEFT JOIN pg_description As d
ON (d.objoid = c.oid AND d.objsubid = 0)
WHERE c.relkind IN('r', 'v') AND d.description > ''
ORDER BY n.nspname, c.relname ;
Column Comments
SELECT n.nspname AS schema_name
, pg_get_userbyid(c.relowner) AS table_owner
, c.relname AS table_name
, a.attname AS column_name
, d.description AS column_description
FROM pg_class AS c
INNER JOIN pg_attribute As a ON c.oid = a.attrelid
INNER JOIN pg_namespace n ON n.oid = c.relnamespace
LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
LEFT JOIN pg_description As d
ON (d.objoid = c.oid AND d.objsubid = a.attnum)
WHERE c.relkind IN('r', 'v')
AND a.attname NOT
IN ('cmax', 'oid', 'cmin', 'deletexid', 'ctid', 'tableoid','xmax', 'xmin', 'insertxid')
ORDER BY n.nspname, c.relname, a.attname;
Shortcut
\d for show all tables
\d tablename to describe table
\? for more shortcuts for redshift
redshift now support show table
show table analytics.dw_users
https://forums.aws.amazon.com/ann.jspa?annID=8641
You can simply use the command below to describe a table.
desc table-name
or
desc schema-name.table-name