What is SQL query with example?

An SQL SELECT statement retrieves records from a database table according to clauses (for example, FROM and WHERE ) that specify criteria. The syntax is: SELECT column1, column2 FROM table1, table2 WHERE column2=’value’;

How do I use AdventureWorks database?

Open SQL Server Management Studio (SSMS) and connect to your SQL Server. Right-click Databases in Object Explorer > Restore Database… to launch the Restore Database wizard. Select Device and then select the ellipses (…) to choose a device. Select Add and then choose the .

What is flag in SQL with example?

You use database flags for many operations, including adjusting SQL Server parameters, adjusting options, and configuring and tuning an instance. When you set, remove, or modify a flag for a database instance, the database might be restarted. The flag value is then persisted for the instance until you remove it.

What is the use of ‘@’ in SQL?

The @CustID means it’s a parameter that you will supply a value for later in your code. This is the best way of protecting against SQL injection. Create your query using parameters, rather than concatenating strings and variables.

How do I write a SQL query?

How to Create a SQL Statement

  1. Start your query with the select statement. select [all | distinct]
  2. Add field names you want to display. field1 [,field2, 3, 4, etc.]
  3. Add your statement clause(s) or selection criteria. Required:
  4. Review your select statement. Here’s a sample statement:

What are the 5 basic SQL commands?

Some of The Most Important SQL Commands

  • SELECT – extracts data from a database.
  • UPDATE – updates data in a database.
  • DELETE – deletes data from a database.
  • INSERT INTO – inserts new data into a database.
  • CREATE DATABASE – creates a new database.
  • ALTER DATABASE – modifies a database.
  • CREATE TABLE – creates a new table.

What is AdventureWorks sample Database?

AdventureWorks Database is a Microsoft product sample for an online transaction processing (OLTP) database. The AdventureWorks Database supports a fictitious, multinational manufacturing company called Adventure Works Cycles.

What is the size of AdventureWorks Database?

You can choose between these editions: OLTP: all you need (48 MB) Lightweight (LT): with a smaller set of data (7 MB) Extended data warehouse (DW_Ext): with a lot more data (883 MB)

What is flag column in SQL?

Tags: Data Warehousing, SQL Server. In data warehousing we have an Is Current Flag column in SCD type 2 dimension table. This flag indicates whether the row is the current version or not. Some DW data modellers believe that in SQL Server platform this column should be created as bit rather than int or Y/N.

How do I add a flag in SQL Server?

In the right pane, right-click the SQL Server service instance and then click Properties. Go to the Startup Parameters tab. In the textbox, type the -T switch command and then click Add. The parameter is added to the Existing parameters list, as shown in Figure 5.

What is like %% in SQL?

The SQL LIKE Operator

The LIKE operator is used in a WHERE clause to search for a specified pattern in a column. There are two wildcards often used in conjunction with the LIKE operator: The percent sign (%) represents zero, one, or multiple characters.

What is == in SQL?

The sql equal operator is used to check whether two expressions are equal or not. If it’s equal, the condition will be true and will return matched records. Not Equal (!=) Operator. The sql not equal operator is used to check whether two expressions are equal or not.

How do I write a query in MySQL?

Some of the commonly used MySQL queries, operators, and functions are as follows :

  1. SHOW DATABASES. This displays information of all the existing databases in the server.
  2. USE database_name. database_name : name of the database.
  3. DESCRIBE table_name.
  4. SHOW TABLES.
  5. SHOW CREATE TABLE table_name.
  6. SELECT NOW()
  7. SELECT 2 + 4;
  8. Comments.

How do I write a SQL script?

To create an SQL script in the Script Editor:

  1. On the Workspace home page, click SQL Workshop and then SQL Scripts. The SQL Scripts page appears.
  2. Click the Create button.
  3. In Script Name, enter a name for the script.
  4. Enter the SQL statements, PL/SQL blocks you want to include in your script.
  5. Click Create.

Is AdventureWorks Database free?

AdventureWorks is a database provided by Microsoft for free on online platforms.

What is SQL AdventureWorks?

SQL Server. AdventureWorks is a sample database for Microsoft SQL Server 2008 to 2014.

How do you add a flag to a table?

How to insert flag icons in tables

  1. 1 Preparing the data. To insert little flag icons in your table, you need flag codes.
  2. 2 Turning the feature on. If you upload your data in this format and go to step 3: Visualize, your table will display the flag codes instead of the flag icons.

What is flag data type?

A flag is one or more data bits used to store binary values as specific program structure indicators. A flag is a component of a programming language’s data structure.

How do you set a trace flag in SQL?

In the right pane, right-click the SQL Server service instance and then click Properties. Go to the Startup Parameters tab.
…
The results returned by a DBCC TRACESTATUS statement include four columns:

  1. TraceFlag. Trace flag number.
  2. Status. If 1, the trace flag is enabled.
  3. Global.
  4. Session.

Is null or is not null?

The IS NULL condition is satisfied if the column contains a null value or if the expression cannot be evaluated because it contains one or more null values. If you use the IS NOT NULL operator, the condition is satisfied when the operand is column value that is not null, or an expression that does not evaluate to null.

How do I start SQL?

4 Step to Getting Started with SQL

  1. Become familiar with basic SQL syntax. You’ll need to understand the basics of SQL syntax, including the functions SELECT, FROM, WHERE, GROUP BY, HAVING, ORDER BY, and LIMIT.
  2. Take an online SQL course.
  3. Start practicing with real data.
  4. Prepare for a job that requires SQL.

Does == works in SQL?

As a result, SQL doesn’t have the problem of ambiguity of = meaning either assignment or equality check. As a result, there is no problem with using = to check equality. On the other hand, in a programming language such as Java, single = is used for assignments, while == is used for comparison.

What is MySQL example?

MySQL is the most widely used database management system software for managing relational databases today. It is an open-source database that is supported by the Oracle Corporation. When compared to Microsoft SQL Server and Oracle Database, it is a quick, scalable, and simple to use database management system.

What is SQL format?

What is an SQL file? A file with . sql extension is a Structured Query Language (SQL) file that contains code to work with relational databases. It is used to write SQL statements for CRUD (Create, Read, Update, and Delete) operations on databases.

How do you write a good SQL query?

  1. Provide Correct Formatting for the Query.
  2. Specify the SELECT fields instead of using SELECT *
  3. Remove Correlated Subqueries if not required.
  4. Limit the results obtained by the query.
  5. Remove The DISTINCT Clause if not required.
  6. Avoid Functions in Predicates.
  7. Avoid OR, AND, NOT operators if possible.