Editing SQL (section)

==Syntax==
{{Main|SQL syntax}}
{{Image frame|content=
<math>
\underbrace{\left. \begin{array}{rl} \textstyle\mathtt{UPDATE~clause\mathtt{:}}  & \{ \mathtt{UPDATE\ \overbrace{\mathtt{countries}}^\mathtt{table}} \} \\                                                                 
    \textstyle\mathtt{SET~clause:} & \{ {\mathtt{SET\ \overbrace{\mathtt{population}}^\mathtt{column} =~} \overbrace{\mathtt{{population} + \underbrace{\mathtt{1}}_\mathtt{literal}}}^\mathtt{expression}} \} \\                 
    \textstyle\mathtt{WHERE~clause:} & \{ {\mathtt{WHERE\ \underbrace{\overbrace{\mathtt{name}}^\mathtt{column} \mathtt{=} \overbrace{{\overbrace{\mathtt{'USA'}}^\mathtt{literal}}}^\mathtt{expression}}_\mathtt{predicate}}\}{\texttt{;}}}
\end{array}
\right \}{\textstyle\texttt{statement}}}_{\textstyle\mathtt{SQL~query}}
</math>
|width=500|caption=A chart showing several of the SQL language elements comprising a single statement}}

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.)<ref name="ANSI/ISO/IEC" />
* ''Expressions'', which can produce either [[scalar (computing)|scalar]] values, or [[table (database)|tables]] consisting of [[column (database)|columns]] and [[row (database)|rows]] of data
* ''Predicates'', which specify conditions that can be evaluated to SQL [[Three-valued logic|three-valued logic (3VL)]] (true/false/unknown) or [[Boolean logic|Boolean]] [[truth value]]s and 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 an important element of ''SQL''.
* ''Statements'', which may have a persistent effect on schemata and data, or may control [[Database transaction|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.
* ''[[Whitespace (computer science)|Insignificant whitespace]]'' is generally ignored in SQL statements and queries, making it easier to format SQL code for readability.