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Displaying posts with tag: syntax (reset)
MySQL 8.0: GROUPING function

Starting with MySQL 8.0.1, the server supports the SQL GROUPING function.  The GROUPING function is used to distinguish between a NULL representing the set of all values in a super-aggregate row  (produced by a ROLLUP operation) from a NULL in a regular row.…

MySQL 8.0.1: Using SKIP LOCKED and NOWAIT to handle hot rows

MySQL 8.0.1 introduces two new features which allow you to better manage situations where you have tables with hot row contention.  This issue frequently presents itself in scenarios such as worker threads all accessing the same tables trying to find new work, and ecommerce websites trying to keep accurate inventory counts.…

MySQL 8.0: Refactoring and Improving the Parser

In 8.0 we have introduced another bunch of parser refactoring worklogs:

  • WL#8067 (me): “Refactoring of the CREATE TABLE statement” with its subtasks:
    • WL#8434: Refactoring of partitioning-related stuff.
    • WL#8435: Cleanup and refactoring column definition stuff.
    • WL#8433: Separate DD commands from regular SQL queries in the parser grammar.

Using git pre-commit hook for php and js syntax check

This is a followup from my two previous posts on php and js git pre-commit syntax check where I had mentioned how to check for php and js syntax independently using pre-commit with git.



But what if we wanted to check for both php and js syntax at same time while committing. So, I used the scripts used for both and combined them. …

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Associating git hooks with js syntax check

This is a followup article from my previous post.


Here we will be using git pre-commit to check for syntax error while committing in JavaScript files.

We will need nodejs in our system. Please check https://nodejs.org/en/ for downloading and install steps.

Note: I am using ubuntu 14.04 for this setup.

Steps to add pre-commit JavaScript syntax check with git:

1. Use npm to install jslint package globally in your system.

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Associating git hooks with php syntax check

Many a times we have faced this problem that when we commit something and it breaks something on the server due to some syntax error.
I know that these can be caught by IDEs and good editors, but sometimes there might be an syntax error introduced after a code merge conflict resolution and commit.
To address this, we can use git pre-commit hooks to check for any syntax errors in the to be committed files.

There is a good script I found which does this at https://github.com/ReekenX/phpcheck-git

Steps to add pre-commit php syntax check with git:

(Issue …

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Inline JSON Path Expressions in MySQL 5.7

MySQL 5.7.9 has a new feature, that simplifies queries that deal with JSON data and makes more human-readable: inlined JSON path expressions. Now you can do following:

mysql> CREATE TABLE employees (data JSON);
Query OK, 0 rows affected (0,01 sec)

mysql> INSERT INTO employees VALUES ('{"id": 1, "name": "Jane"}');
Query OK, 1 row affected (0,00 sec)

mysql> INSERT INTO employees VALUES ('{"id": 2, "name": "Joe"}');
Query OK, 1 row affected (0,00 sec)

mysql> SELECT * FROM employees WHERE data->'$.id'= 2;

+--------------------------+
| data                     |
+--------------------------+
| {"id": 2, "name": "Joe"} |
+--------------------------+
1 row in set (0,01 sec)

Let’s take a closer look at the expression in the WHERE clause.…

Log Buffer #428: A Carnival of the Vanities for DBAs

The Log Buffer Edition once again is sparkling with some gems, hand-picked from Oracle, SQL Server and MySQL.

Oracle:

  • Oracle GoldenGate 12.1.2.1.1  is now certified with Unity 14.10.  With this certification, customers can use Oracle GoldenGate to deliver data to Teradata Unity which can then automate the distribution of data to multiple Teradata databases.
  • How do I change DNS servers on Exadata storage servers.
  • Flushing Shared Pool Does Not Slow Its Growth.
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Should I Put That Table Alias or Not?

Infrequent SQL developers often get confused about when to put parentheses and/or aliases on derived tables. There has been this recent Reddit discussion about the subject, where user Elmhurstlol was wondering why they needed to provide an alias to the derived table (the subselect with the UNION) in the following query:


SELECT AVG(price) AS AVG_PRICE
FROM (
  SELECT price from product a JOIN pc b
  ON a.model=b.model AND maker='A'
  UNION ALL
  SELECT price from product a JOIN laptop c
  ON a.model=c.model and maker='A'
) hello

The question really was about why the "hello" table alias was necessary, because often it seems not to be required.

Here’s what the SQL standard states

If in doubt, it is often useful to consider the SQL standard about the rationale behind some …

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MySQL Idiosyncrasies That Bite

The following are my slides that I presented at ODTUG Kaleidoscope 2010. This presentation talks about the MySQL defaults including a non-transactional state, silent data truncations, date management, and transaction isolation options. These are all critical for data integrity and consistency. I also cover in-depth topics including SQL_MODE, character sets and collations.

MySQL Idiosyncrasies That Bite View more presentations from Ronald Bradford.

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