SQL Operators and Operands

In order to use a computer language, you usually give instructions to an internal program. An instruction can be formulated as a command. Examples are "give me food" or "touch your head". Another type of instruction can be formulated as a question. Examples are "what time is it?" or "Are you hungry?". The sentence or group of words that constitute an instruction is also called a statement.

Related Tutorials

Database Operators and Operands
The fields we have been using allow the user to enter, view, or change data of a database. Because there is so many types of values a user can be ask to deal with, the values in the fields are categorized by types. Learn: Overview of Operators and Operands, Constants, Operators, Logical Operators.

Logical Operators in Access SQL
Originally, logical operators were a concept from algebra used to exclude and include number sets. They are, very simply, NOT, AND, and OR. Sometimes this set is expanded to combinations of the operators, but at core it's only these three. The logical operators are often referred to as the Boolean operators.

Table of operators
An operator is a sign or symbol that specifies the type of calculation to perform within an expression. There are mathematical, comparison, logical, and reference operators. Access supports a variety of operators, including arithmetic operators such as +, -, multiply (*), and divide (/), in addition to comparison operators for comparing values, text operators for concatenating text, and logical operators for determining true or false values. This article provides details about using these operators.

SQL - Multiple Conditions; using the AND and OR conditions
SQL allows us to combine two or more simple conditions by using the AND and OR or NOT operators. Any number of simple conditions can be present in a single SQL statement, to allow us to create complex WHERE clauses that allow us to control which rows are included in our query results.

Exploring Data Analysis
To further enhance your filtering capabilities, you can use Boolean algebra combined with the operators we have used so far. Besides the logical operators we know already, Boolean algebra adds extra operators used to concatenate expression.

Introduction to DAO, ADO, ADOX, and SQL
Microsoft Access ships with a language named Visual Basic For Applications, or VBA. This allows you to complement MS Access with code that can perform complex operations. This language is used throughout the Microsoft Visual Office family of applications, including Microsoft Excel, Work, PowerPoint, Visio, etc. This language is also used by applications published by companies other than Microsoft. An example is Autodesk that publishes AutoCAD. To customize the VBA language for our database environment, Microsoft Access includes a library called Microsoft Access Object Library. Topics Microsoft Access Object Library and VBA, Microsoft Data Access Objects, Database Creation With DAO, The Structured Query Language, Introduction to SQL Operators, Unary Operators, Binary Operators, Microsoft ActiveX Data Objects, ADOX Fundamentals, The Data Source of an Application and The Connection to a Database.

Operators and Operands
Microsoft Access and Microsoft Visual Basic are not case-sensitive. Therefore, any word we are going to use that involves a field, its name, and new words we will introduce in this section, whether written in uppercase, lowercase or a mix, as long as it is the same word, represents the same thing. Based on this, the words TRUE, True and true, as related to Microsoft Access, represent the same word. In the same way, if the words NULL, Null, and null are used in an expression, they represent the same thing.

Nest a query inside another query or in an expression by using a subquery
Sometimes you may want to use the results of a query as a field in another query, or as a criterion for a query field. For example, suppose that you want to see the interval between orders for each of your products. To create a query that shows this interval, you need to compare each order date to other order dates for that product. Comparing these order dates also requires a query. You can nest this query inside of your main query by using a subquery (subquery: An SQL SELECT statement that is inside another select or action query.). You can write a subquery in an expression (expression: Any combination of mathematical or logical operators, constants, functions, and names of fields, controls, and properties that evaluates to a single value. Expressions can perform calculations, manipulate characters, or test data.) or in a Structured Query Language (SQL) statement in SQL view (SQL view: A window that displays the SQL statement for the current query or that is used to create an SQL-specific query (union, pass-through, or data definition). When you create a query in Design view, Access constructs the SQL equivalent in SQL view.).

Convert Microsoft Access (JET SQL) to SQL Server (T-SQL) Cheatsheet
Lots of questions come up in the SQL Team forums about conversions between Access and T-SQL and some of the differences between the two SQL dialects. Here's a few handy things to help you out with converting your projects. Check in now and then as this short list will eventually grow as more things come up.

Access SQL (VB6)
In this page, I'll focus on Jet's SQL dialect and show you what you can do with SQL (almost everything), what you can't do with Jet SQL (there are several key things that can't be done), and where SQL works better than Jet Data Access Objects for working with a database.

Microsoft Access SQL Tutorials
Here you will find articles relating to SQL (Structured Query Language) and SQL use and implementation in Microsoft Access. You will find articles and topics relating to SQL query designs, from planning what tables and fields will be used to selecting criteria to be used in the SQL Statements. There are articles on SQL basics, SQL Select, Insert, Update and Delete Statements and topics on why use SQL.

Converting Access Queries to SQL Server
Here are the conversion topics we will address: 1. Replacements for VBA functions; Date() and Now() 2. T-SQL equivalents for InStr() and Mid() 3. How to convert the IIF() function to T-SQL 4. Merciless T-SQL string concatenation explained 5. Stored Procedure verses View dilemma 6. Suggestions for advanced issues: T-SQL Functions

SQL Queries
You need to become familiar with SQL (Structured Query Language) because you will need it if you ever develop a Microsoft Access application and have to issue queries through code. You also need SQL to query other database systems, such as Oracle and MySql. Finally, once you know SQL, it is often easier to write a query directly in SQL than to design it using Access's QBE interface.

Introduction to SQL
The Structured Query Language (SQL) is the most popular language used in computers to create and manage databases. SQL is a language with its own syntax and grammar. SQL is a universal language that doesn't belong to a particular company. This makes it easy for different companies or programming environments to adopt it. In this site, we will study techniques of creating databases and we will use the SQL.

Comparison of Microsoft Access SQL and ANSI SQL
Microsoft Access database engine SQL is generally ANSI-89 Level 1 compliant. However, certain ANSI SQL features are not implemented in Microsoft Access SQL. Conversely, Microsoft Access SQL includes reserved words and features not supported in ANSI SQL.

Using SQL to Generate SQL Statements
Learn the benefits of generating SQL statements from a query, how to make the output from a query appear in the form of another SQL statement and how to use the data dictionary, database tables, or both to form SQL statements.

Access SQL: basic concepts, vocabulary, and syntax
When you want to retrieve data from a database, you ask for the data by using Structured Query Language, or SQL. SQL is a computer language that closely resembles English, but that database programs understand. Every query that you run uses SQL behind the scenes. Understanding how SQL works can help you create better queries, and can make it easier for you to understand how to fix a query that is not returning the results that you want. This is one of a set of articles about Access SQL. This article describes the basic use of SQL to select data, and uses examples to illustrate SQL syntax. In this article * What is SQL? * Basic SQL clauses: SELECT, FROM, and WHERE * Sorting the results: ORDER BY * Working with summarized data: GROUP BY and HAVING * Combining query results: UNION

Introduction Structured Query Language
This page is a tutorial of the Structured Query Language (also known as SQL) and is a pioneering effort on the World Wide Web, as this is the first comprehensive SQL tutorial available on the Internet. SQL allows users to access data in relational database management systems, such as Oracle, Sybase, Informix, Microsoft SQL Server, Access, and others, by allowing users to describe the data the user wishes to see. SQL also allows users to define the data in a database, and manipulate that data. This page will describe how to use SQL, and give examples. The SQL used in this document is "ANSI", or standard SQL, and no SQL features of specific database management systems will be discussed until the "Nonstandard SQL" section.

Introduction to Structured Query Language
This page is a introductory tutorial of the Structured Query Language (also known as SQL) and is a pioneering effort on the World Wide Web, as this is the first comprehensive SQL tutorial available on the Internet. SQL allows users to access data in relational database management systems, such as Oracle, Sybase, Informix, Microsoft SQL Server, Access, and others, by allowing users to describe the data the user wishes to see. SQL also allows users to define the data in a database, and manipulate that data. This page will describe how to use SQL, and give examples. The SQL used in this document is "ANSI", or standard SQL, and no SQL features of specific database management systems will be discussed until the "Nonstandard SQL" section.

Learn Database SQL Technology
Structured Query Language (SQL) is a language that was developed by IBM for processing data in mainframe databases. The relational nature of databases and the ease of SQL usage has made SQL the standard language for databases. SQL technology is also standardized which makes it ideal for usage across multiple fields. Learning SQL database technology will enable you to program and maintain any database with ease.

Basic queries using SQL
Query-By-Example (QBE) and Structured Query Language (SQL) are both well-known, industry standard languages for extracting information from relational database systems. The advantage of QBE that it is graphical and relatively easy to use. The advantage of SQL is that it has achieved nearly universal adoption within the relational database world. Learning objectives: understand the difference between QBE and SQL; create an SQL query; use SQL as a data definition language. (pdf file install Acrobat Reader to read this tutorial)

Create a SQL Query
SQL queries use Structured Query Language (SQL), a standard scripting language, to make requests from databases. You can use four types of SQL queries in Access 97: union, pass-through, data-definition and subquery.

Import or link to SQL Server data
If your department or workgroup uses Microsoft SQL Server to store data, you might encounter scenarios where you need to work with some of the SQL Server data in Microsoft Office Access 2007. This article describes the steps both for importing and for linking SQL Server data into Access 2007. What do you want to do? * Import SQL Server data * Link to SQL Server data * Learn how Access interprets SQL Server data types

SQL Queries in Microsoft Access
Microsoft Access is and excellent package for handling databases. Its query feature is used to retrieve data in desired formats. You can also use SQL Queries. SQL queries are those that are created using the various SQL commands like SELECT, DELETE, UPDATE or APPEND

Dynamic Uses of SQL
Learn how various commercial products--Personal Oracle7, open database connectivity (ODBC), InterBase ISQL, Microsoft's Visual C++, and Borland's Delphi--relate to SQL, How to set up your environment for SQL, How to create a database using Oracle7, Microsoft Query, and InterBase ISQL, How to use SQL inside applications written in Visual C++ and Delphi. After reading this material, you will know where to start applying your new SQL skills.

Why use SQL?
A descendent of the 70’s SEQueL standard, SQL has aged well and is still the tool most favoured by database administrators across the globe. There are two essential purposes of a database language:- to create and edit the database and to perform queries. The simple fact is that these tasks are accomplished by users of SQL and SQL powered applications with generally greater ease and efficiency, and that no-one has yet come up with a better way of working with data in a relational database.

Introduction to SQL (Structured Query Language) (VB6)
This tutorial explains in great depth how the SQL language works. It has many examples and uses access databases to demonstrate the SQL syntax.

Microsoft Access Query Operators
Queries are a very important feature of Microsoft Access that can tell you information about the data stored in the Access tables. Queries make it easier to search the data from different fields. Therefore, using queries to achieve the results you are looking for is quite a useful tool. However, when you have large amounts of information, you will need more advanced techniques such as Boolean Operators to make sense of the queries you have inputted.

Using String Function in your Access SQL Queries
When writing our SQL queries in Access there may be times when we want to manipulate the data that is contained in the columns rather than just returning the whole column value. In this article the guys from SQL Book outline some useful functions that can be used in our SQL queries to manipulate string values and give some real world examples of them in use.

Migrating from Access 2000 to SQL Server 2000
In this article, we will simulate migrating a relatively small but established business from Microsoft Access 2000 to SQL Server 2000. There are a variety of reasons a business might wish to perform such a migration. Legacy queries, forms, and reports will be taken into consideration, as well as the appropriate way to handle database files. Growing businesses often come to a stage where they need to migrate their MS Access database to a SQL Server. TOC: Migrating from Access 2000 to SQL Server 2000; MS Access: User Created Objects; Creating a SQL 2000 Server database; Exporting tables from MS Access 2000 to SQL 2000 Server; Establishing links to SQL 2000 Server database; Verifying functionality of existing objects.

Aggregate Functions in SQL and Microsoft Access
With SQL there are many functions available that allow you to perform or manipulate calculations on your data. These functions can be used as part of the SQL SELECT statement.

Advanced SQL Topics
Today's purpose is to cover advanced SQL topics, which include the following: Temporary tables, cursors, Stored procedures, Triggers and Embedded SQL.

How to Write a SELECT Statement in SQL
A SQL SELECT statement can be broken down into four basic parts. More advanced SQL statements can contain other keywords, but these four make up the core of most queries.

SQL Aggregate Functions
Using the SQL aggregate functions, you can determine various statistics on sets of values. You can use these functions in a query and aggregate expressions in the SQL property of a QueryDef object or when creating a Recordset object based on an SQL query.

DELETE and UPDATE Data using SQL
In continuation of our exploration of the DML (Data Manipulation Language) components of SQL (Structured Query Language), here we introduce two more fundamental commands - SQL DELETE and SQL UPDATE. These two commands are used to edit the contents of the database, and do not alter the underlying structure of the database.

Use a SQL statement to delete data
Writing SQL to delete data from an MS Access table is just about the easiest SQL statement you can write. This example will use the SQL statement to create an Access query, but you can use the statement in a macro or VBA as well.

Use a control in an SQL statement in Access
In Access 2003/XP/2000/97, I've created a form where the user enters a value in a textbox. I want to use this value to create an SQL statement. How do I use a control's value in an SQL statement in VBA code?

The SQL Select Statement
Microsoft Access is a Visual Basic based application that allows the SQL statements to be embedded in VBA code and macros. One of the most used SQL statements, the SELECT statement, provides the much needed flexibility in the retrieval of data from a database.

Migrating Access Apps to SQL Server
Query optimization is not simple, but there are things you can do. This article has outlined some development concepts that will, without question, improve performance. Additional improvement will be realized when SQL Queries are tuned to use SQL Server more efficiently. There is no magic bullet but with some concerted effort, these suggestions will have your application humming in no time

SQL Operators and Operands

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