SQL
Structured Query Language
| # | Topic Title | Description | Order |
|---|---|---|---|
| 1. | Structured Query Language | • SQL stands for Structured Query Language, which enables people to create databases, add new data to them, maintain the data in them, and retrieve selected parts of the data. Developed in the 1970s at IBM, SQL has grown and advanced over the years to become the industry standard. It is governed by a formal standard maintained by the International Standards Organization (ISO). • SQL began as a language used to manipulate data in relational databases, it has evolved to be a language for manipulating data across various database technologies. | 0 |
| 2. | SQL STATEMENTS | The SQL command language consists of a limited number of statements that perform three functions of data handling: Some of them define data, some manipulate data, and others control data. | 1 |
| 3. | LOGICAL OPERATORS | In SQL, logical operators are used to create conditional expressions that evaluates to either true or false. They are used in the WHERE clause of SELECT, UPDATE, DELETE, and other SQL statements to filter data based on specified conditions. | 2 |
| 4. | SORTING AND LIMITING RESULTS | Sorting data with ORDER BY | 3 |
| 5. | GROUPING DATA AND FILTERING GROUPS | GROUPING DATA AND FILTERING GROUPS | 4 |
| 6. | AGGREGATE FUNCTIONS | • Set functions apply to sets of rows in a table rather than to a single row. These functions summarize some characteristic of the current set of rows. The set may include all the rows in the table or a subset of rows that are specified by a WHERE clause. • Programmers sometimes call set functions aggregate functions because these functions take information from multiple rows, process that information in some way, and deliver a single-row answer. | 5 |