SQL Where Clause Example | SQL Where Query Tutorial is today’s topic. The WHERE clause is used to filter the database records. The WHERE clause is used to extract only those records that fulfill the specified condition. The SQL WHERE clause is used to specify the condition while fetching the data from a single table or by joining the multiple tables. If a given condition is satisfied, then only it returns the specific value from the table. You should use a WHERE clause to filter the records and fetching the necessary records.

SQL Where Clause Example

The WHERE clause is not only used in the SELECT statement; it is also used in an UPDATE, DELETE statement. The syntax of a SELECT statement with a WHERE clause is following.

SELECT column1, column2, columnN 
FROM table_name
WHERE [condition]

“SELECT column1, column2, column3 FROM tableName” is the standard …

Introduction In this article, we are going to see how a relational database executes SQL statements and prepared statements. SQL statement lifecycle The main database modules responsible for processing a SQL statement are: the Parser, the Optimizer, the Executor. A SQL statement execution looks like in the following diagram. Parser The Parser checks the SQL statement and ensures its validity. The statements are verified both syntactically (the statement keywords must be properly spelled and following the SQL language guidelines) and semantically (the referenced tables and column do exist in the database). During... Read More

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SQL Create Table Statement Example | Create Table in SQL Tutorial is today’s topic. A CREATE TABLE statement is used to create a new table in the database. SQL is the Standard Query Language for manipulating, storing and retrieving data in databases. SQL is used in MySQL, SQL Server, MS Access, Oracle, Sybase, Informix, Postgres, and other database systems. SQL stands for Structured Query Language. SQL lets you access and manipulates databases. RDBMS stands for Relational Database Management System. RDBMS is the basis for SQL, and for all modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.

SQL Create Table Statement Example

Working with SQL for data analysis and manipulation sometimes requires creating the new tables. Requirements like, Do you want to store the output of your SQL queries? Do you need to pull the new data sources (for example, csv files) into your data …

What's a good natural key? This is a very difficult question for most entities when you design your schema. In some rare cases, there seems to be an "obvious" candidate, such as a variety of ISO standards, including: ISO 639 language codesISO 3166 country codesISO 4217 currency codes But even in those cases, there might … Continue reading The Cost of Useless Surrogate Keys in Relationship Tables →

I have had some requests to write some blogs on the basics of using PHP and MySQL together.  This will not be a series for the experienced as it will start at a level where I will go into a lot of details but expect very few prerequisites from the reader.  If this is not you, please move on. If it is you and you read something you do not understand, please contact me to show me where I assumed too much.

PHP and MySQL are both in their mid twenties and both vital in the worlds of developers.  With the big improvements in PHP 7 and MySQL 8, I have found a lot of developers flocking to both but stymied by the examples they see as their are many details not explained. So let's get to the explaining!
1. Use the latest software
If you are not using PHP 7.2 or 7.3 (or maybe 7.1) then you are missing out in features and performance.  The PHP 5.x series is deprecated, no longer support, and …

Wondering which databases are trending in 2019? We asked hundreds of developers, engineers, software architects, dev teams, and IT leaders at DeveloperWeek to discover the current NoSQL vs. SQL usage, most popular databases, important metrics to track, and their most time-consuming database management tasks. Get the latest insights on MySQL, MongoDB, PostgreSQL, Redis, and many others to see which database management systems are most favored this year.

SQL vs. NoSQL

As any database administrator knows, the first question you have to ask yourself is whether to use a SQL or NoSQL database for your application. …

IS NULL, IS NOT NULL, truthiness among other assertions on MySQL and PostgreSQL

People like to complain about JavaScript, how can one thing be equal to the other, i.e. null == undefined evaluates to true unless you use the triple equals ===. Other dynamic typed languages have its peculiarities, such as Ruby where 0 == true evaluates to true, the reason for Ruby is that considers 0 as a value and any value evaluates to true.

How about SQL? The answer is… it depends.

Which database are you using?

Some may be more forgiving, like MySQL doing casts for you all over the place, or more strict like PostgreSQL where you can only compare the truthiness of something of the same type.

Want to deploy WordPress 5.0 on the Now platform by ZEIT? Our friends over at ZEIT’s Now global serverless deployment platform whipped up a great tutorial for WordPress5-on-Now using cheap MySQL hosting instances from ScaleGrid. With such strong interest in this installation, we decided to write up the steps to configure your MySQL database on the ScaleGrid side to get you up and running ever faster with WordPress on Now.

Leave your comments: https://t.co/exuBzSHkHM
@now/wordpress summary:
◆ λ size = 13mb
◆ Just needs `wp-config.php`
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In a MySQL hosting replication setup, the parameter Seconds_Behind_Master (SBM), as displayed by the SHOW SLAVE STATUS command, is commonly used as an indication of the current replication lag of the slave. In this blog post, we examine how to understand and interpret this value in various situations.

Possible Values of  Seconds Behind Master

The value of SBM, as explained in the  MySQL documentation, depends on the state of the MySQL slave in general, and the states of MySQL slave SQL_THREAD and IO_THREAD in particular. While IO_THREAD connects with the master and reads the updates, SQL_THREAD applies these updates on the slave. Let’s examine the possible values of SBM during different states of the MySQL Slave.

When SBM Value is Null

• SBM is …

MySQL 8.0.14 came with Lateral Derived Tables as a new feature.  But what is that and how do you use them?

Let's start what a derived table is.  According to the manual (link below) A derived table is an expression that generates a table within the scope of a query FROM clause.   You are probably used to using a subquery or JSON_TABLE where that query feeds data into another query.

Derived Tables

Derived tables can return a scalar, column, row, or table. But there are limits to their use.
A derived table cannot be a correlated subquery and a derived table cannot contain references to other tables of the same SELECT. And previous to MySQL 8.0.14, a derived table cannot contain outer references.

Okay, so what is an 'outer reference'? The SQL-92 standard …