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:

    ““What may this mean? Language of Man pronounced
    By tongue of brute, and human sense expressed!
    The first at least of these I thought denied
    To beasts, whom God on their creation-day
    Created mute to all articulate sound;
    The latter I demur, for in their looks
    Much reason, and in their actions, oft appears.”
    —John Milton (1608–1674)

    “Nature confounds her summer distinctions at this season. The heavens seem to be nearer the earth. The elements are less reserved and distinct. Water turns to ice, rain to snow. The day is but a Scandinavian night. The winter is an arctic summer.”
    —Henry David Thoreau (1817–1862)