SQL - Language Elements

Language Elements

The SQL language is subdivided into several language elements, including:

  • Clauses, which are constituent components of statements and queries. (In some cases, these are optional.)
  • Expressions, which can produce either scalar values or tables consisting of columns and rows of data.
  • Predicates, which specify conditions that can be evaluated to SQL three-valued logic (3VL) or Boolean (true/false/unknown) truth values and which are used to limit the effects of statements and queries, or to change program flow.
  • Queries, which retrieve the data based on specific criteria. This is the most important element of SQL.
  • Statements, which may have a persistent effect on schemata and data, or which may control transactions, program flow, connections, sessions, or diagnostics.
    • SQL statements also include the semicolon (";") statement terminator. Though not required on every platform, it is defined as a standard part of the SQL grammar.
  • Insignificant whitespace is generally ignored in SQL statements and queries, making it easier to format SQL code for readability.

Read more about this topic:  SQL

Famous quotes containing the words language and/or elements:

    “Theoretically, I grant you, there is no possibility of error in necessary reasoning. But to speak thus “theoretically,” is to use language in a Pickwickian sense. In practice, and in fact, mathematics is not exempt from that liability to error that affects everything that man does.”
    —Charles Sanders Peirce (1839–1914)

    “The three great elements of modern civilization, gunpowder, printing, and the Protestant religion.”
    —Thomas Carlyle (1795–1881)