This section is not intended to be a course of the SQL language. Therefore, the focus will be put on the minimal set of differences that you must know in order to write queries properly.

A pure JavaScript database

SQL Cloud is a 100% JavaScript database running on the browser (Chrome, Safari, Edge, Firefox…) and any device (PC, tablet, mobile..).

It is read-only at the moment (no INSERT, UPDATE, DELETE).

The engine and the full data model (tables, indexes, etc.) are created when the HTML page is opened and everything is destroyed when the page is closed.

All the users run their own SQL Cloud database instance fully isolated from the rest.

All tables have no data and they are populated in real-time fetching data over the Atlassian’s Jira public REST API to answer the users' queries.

Show tables and columns

Explore the data model with these commands:

• show tables

• show columns from <table>

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title Example
Code Block language sql show tables Run the statement above to list all the tables available in the database model And Code Block language sql show columns from <table> to display the column and their metadata of a given table:

Strings vs aliases

Like in the rest of the database implementations a string is enclosed between single quotes.

...

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title Example
Code Block language sql SELECT 'This is a string' as `Column Alias` FROM DUAL `Table alias`

Table, column and function names are case sensitive

• Use Uppercase names

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title Example
Code Block language sql select * from PROJECT will work. Whereas Code Block language sql select * from project will not.

KEY is a reserved word

As other database vendors, SQL Cloud does have reserved words that must be surrounded with accents or square brackets

SELECT `KEY` FROM PROJECT

SELECT [KEY] FROM PROJECT

No schema support

Many database vendors group tables into schemas (i.e.: PUBLIC). SQL Cloud does not support schemes.

Reckless queries (AKA Full scans) are not allowed

Many times, users write reckless queries that requite to scan/fetch all the records on a table to be answered.

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title Read more...
This can cause series reliability problems and compromise the Jira server instance performance. A clear example is: Code Block language sql SELECT * FROM ISSUE What if there are millions of records/issues? Therefore many queries performing full scans on tables are aborted by the SQL Cloud engine by raising a Full Scan error: Since SQL Cloud is a wrapper for the Atlassian’s Jira public REST API, it relies on the underlaying Atlassian’s API for that. In other words, if the Jira REST API allows querying for all the results (i.e.: PROJECTs), then SQL Cloud will allow it too. Otherwise (i.e.: ISSUEs) not. In this case the indexed column names are displayed (JQL and ID in the example above). An indexed column in SQL Cloud corresponds to a filter parameter required by the Atlassian’s Jira public REST API to fetch data from Jira. For instance, you can search for issues in Jira by ID or by JQL query. In general, the SQL Cloud is an straightforward implementation of the Jira REST API and inherits the same security and the rest of the constraints.

WHERE conditions are not the same as JOIN conditions

In SQL Cloud there is a big difference about how values are provided for dynamic table resolution (fetching data from Jira to populate them).

Understating this is very important to write working queries that perform optimally.

Aggregation conditions do not support aliases

SELECT `i`.`KEY`as `Issue`, count(*) as `Num. comments`
FROM ISSUE `i`
LEFT JOIN ISSUECOMMENT `ic` ON `ic`.`ISSUEID` = `i`.`ID`
WHERE `i`.`JQL` = 'PROJECT = TALH'
GROUP BY `i`.`KEY`
HAVING count(*) > 2

SELECT `i`.`KEY`as `Issue`, count(*) as `Num. comments`
FROM ISSUE `i`
LEFT JOIN ISSUECOMMENT `ic` ON `ic`.`ISSUEID` = `i`.`ID`
WHERE `i`.`JQL` = 'PROJECT = TALH'
GROUP BY `i`.`KEY`
HAVING `Num. comments` > 2