SQL Queries with xPath Expressions for finding similar values - sql

This uses oracle database to store the data using the XML type, I was wondering is there any way to do a query to output the name of the people of who are swimmer and teachers? probably alot easier than i think
<swimmer>
<swimmer name>John Goldrick</swimmer name>
<swimmer name>James John</swimmer name>
<teacher>
<teacher name>John Goldrick</teacher name>
</swimmer>
</teacher>

Related

Get query used to create a table

We use snowflake at work to store data, and for one of the tables, I dont have the SQL query used to create the table. Is there a way to see the query used to make that table?
I tried using the following
get_ddl('table', 'db.table', true)
but this gives me an output like-
This doesnt give me any information about the sql query that was used. How do I get that in snowflake?
If get_ddl() is not enough you may use INFORMATION_SCHEMA.
To get more information you have 2 options:
Use the QUERY_HISTORY() table functions: https://docs.snowflake.com/en/sql-reference/functions/query_history.html
Use the QUERY_HISTORY() view: https://docs.snowflake.com/en/sql-reference/account-usage/query_history.html
If you use the funtions/view above and filter all the records by QUERY_TEXT, maybe you get more information about the exact SQL that was used to create your table.

How can I control the SQL table aliases that Hibernate uses in its generated queries?

tl;dr: Hibernate automatically generates SQL table aliases in its queries like jurisdicti4_ or this_. Here's an example query:
SELECT
this_.id AS id2_6_3_,
this_.a_table_column AS a_table_column3_6_3_,
jurisdicti4_.b_table_column AS b_table_column4_6_3_,
FROM
app_table_a this_
LEFT OUTER JOIN jurisdiction jurisdicti4_ ON this_.jurisdiction = jurisdicti4_.name
WHERE
this_.a_table_column = ?
I'm using the Hibernate Criteria API to add some hints that need reference the SQL aliases in the query, so I need to know how to either:
specify the SQL table aliases Hibernate will use in its queries (e.g. tell it to use juris instead of jurisdicti4_ for jurisdiction, or
get hibernate to tell me the exact SQL table alias it will use for a particular table or entity (e.g. be told the alias in the query for jurisdiction will be jurisdicti4_.
Full story:
I've inherited a Java app with an Oracle DB that uses Hibernate 4.3.8 and the Hibernate Criteria API to generate some complicated search queries. It recently ran into a severe SQL performance problem that will require us to start to include hints these queries. However, we use Oracle, and its index hints are in the form of:
/*+ index (TABLE_ALIAS INDEX_NAME) */
I've successfully added the needed hints using Criteria.addHint(...), however I've had to hardcode the Hibernate-generated TABLE_ALIAS in the hint string. I'm concerned that over time, the aliases may change, so I want to either control how they're generated or be able to retrieve their values to use when adding the SQL hint.
Edit: This website describes the Hibernate SQL alias generation process: https://prismoskills.appspot.com/lessons/Hibernate/Chapter_23_-_Hibernate_alias_names.jsp
I've found that I have partial control of the SQL aliases when I programmatically set up the join like this: criteria.createAlias(associationPath, alias). The alias value I pass seems to be used as the first part of the SQL alias for the table. However, Hibernate appends some kind of generated table ID integer to that, so I'd get something like myalias4_ in the generated SQL. Also, this only seems to work in joins I setup myself in the criteria. Hibernate will often add its own based on the mappings, and I'm not sure how get this same level of partial control over those.

Adding today date in Table name when using Create Table function in standard sql GBQ

I am quite new to GBQ and any help is appreciated it.
I have a query below:
#Standard SQL
create or replace table `xxx.xxx.applications`
as select * from `yyy.yyy.applications`
What I need to do is to add today's date at the end of the table name so it is something like xxx.xxx.applications_<todays date>
basically create a filename with Application but add date at the end of the name applications.
I am writing a procedure to create a table every time it runs but need to add the date for audit purposes every time I create the table (as a backup).
I searched everywhere and can't get the exact answer, is this possible in Query Editor as I need to store this as a Proc.
Thanks in advance
BigQuery doesn't support dynamic SQL at the moment which means that this kind of construction is not possible.
Currently BigQuery supports Parameterized Queries but its not possible to use parameters to dynamically change the source table's name as you can see in the provided link.
BigQuery supports query parameters to help prevent SQL injection when
queries are constructed using user input. This feature is only
available with standard SQL syntax. Query parameters can be used as
substitutes for arbitrary expressions. Parameters cannot be used as
substitutes for identifiers, column names, table names, or other parts
of the query.
If you need to build a query based on some variable's value, I suggest that you use some script in SHELL, Python or any other programming language to create the SQL statement and then execute it using the bq command.
Another approach could be using the BigQuery client library in some of the supported languages instead of the bq command.

Use table description in Hive query

I would like to use DESCRIBE table statement results dynamically in another query in Hive. Is it possible? I cannot find any proper way of solving this problem.
It should be similar to using all_tab_columns view from Oracle RDBMS.

How do you port a SqlServer database to MySQL?

I have a SqlServer db that I would like to port to MySQL. What's the best way to to this. Things that need to be ported are:
Tables (and data)
FileStream → MySQL equivalent?
Stored Procedures
Functions
Data types are relatively similar.
There is no equivalent to FileStream in MySQL - the files must either be stored as BLOBs, or on the file system while the path is stored in the database.
Migrating away from TSQL means:
There's no WITH clause in MySQL - it will have to converted into a derived table/inline view
There's no TOP syntax - these have to be converted to use LIMIT
There's no ranking/analytic functionality in MySQL - can't use ROW_NUMBER, RANK, DENSE_RANK or NTILE. See this article for alternatives.
MySQL views have notoriously limited functionality:
The SELECT statement cannot contain a subquery in the FROM clause.
The SELECT statement cannot refer to system or user variables.
Within a stored program, the definition cannot refer to program parameters or local variables.
The SELECT statement cannot refer to prepared statement parameters.
Any table or view referred to in the definition must exist. However, after a view has been created, it is possible to drop a table or view that the definition refers to. In this case, use of the view results in an error. To check a view definition for problems of this kind, use the CHECK TABLE statement.
The definition cannot refer to a TEMPORARY table, and you cannot create a TEMPORARY view.
Any tables named in the view definition must exist at definition time.
You cannot associate a trigger with a view.
As of MySQL 5.0.52, aliases for column names in the SELECT statement are checked against the maximum column length of 64 characters (not the maximum alias length of 256 characters).
Dynamic SQL will have to be converted to use MySQL's Prepared Statement syntax
A guide/article with some useful tips is available on the official MySQL dev site.
This is not for the faint of heart. Here is an article that explains what you are in for:
http://searchenterpriselinux.techtarget.com/news/column/0,294698,sid39_gci1187176,00.html