feat: Support SET TIME ZONE syntax

Signed-off-by: Alex Qyoun-ae <4062971+MazterQyou@users.noreply.github.com>

Author: MazterQyou

src/ast/mod.rs

@@ -1045,6 +1045,16 @@ pub enum Statement {
         charset_name: String,
         collation_name: Option<String>,
     },
+    /// SET [ SESSION | LOCAL ] TIME ZONE timezone
+    ///
+    /// Note: this is a PostgreSQL-specific statement,
+    /// but may also compatible with other SQL.
+    SetTimeZone {
+        local: bool,
+        // SESSION is the default if neither SESSION nor LOCAL appears.
+        session: bool,
+        timezone: Expr,
+    },
     /// SHOW <variable>
     ///
     /// Note: this is a PostgreSQL-specific statement.
@@ -1849,6 +1859,20 @@ impl fmt::Display for Statement {
 
                 Ok(())
             }
+            Statement::SetTimeZone {
+                local,
+                session,
+                timezone,
+            } => {
+                let modifier = if *local {
+                    "LOCAL "
+                } else if *session {
+                    "SESSION "
+                } else {
+                    ""
+                };
+                write!(f, "SET {}TIME ZONE {}", modifier, timezone)
+            }
             Statement::ShowVariable { variable } => {
                 write!(f, "SHOW")?;
                 if !variable.is_empty() {

src/parser.rs

@@ -3769,6 +3769,19 @@ impl<'a> Parser<'a> {
             });
         }
 
+        if dialect_of!(self is PostgreSqlDialect | RedshiftSqlDialect)
+            && self.parse_keywords(&[Keyword::TIME, Keyword::ZONE])
+        {
+            let local = modifier == Some(Keyword::LOCAL);
+            let session = modifier == Some(Keyword::SESSION);
+            let timezone = self.parse_expr()?;
+            return Ok(Statement::SetTimeZone {
+                local,
+                session,
+                timezone,
+            });
+        }
+
         let mut key_values: Vec<SetVariableKeyValue> = vec![];
 
         if dialect_of!(self is PostgreSqlDialect | RedshiftSqlDialect) {

tests/sqlparser_postgres.rs

@@ -949,6 +949,45 @@ fn parse_set_role() {
     );
 }
 
+#[test]
+fn parse_set_time_zone() {
+    let stmt = pg().verified_stmt("SET SESSION TIME ZONE DEFAULT");
+    assert_eq!(
+        stmt,
+        Statement::SetTimeZone {
+            local: false,
+            session: true,
+            timezone: Expr::Identifier(Ident {
+                value: "DEFAULT".to_string(),
+                quote_style: None,
+            }),
+        }
+    );
+
+    let stmt = pg().verified_stmt("SET LOCAL TIME ZONE 'Europe/Rome'");
+    assert_eq!(
+        stmt,
+        Statement::SetTimeZone {
+            local: true,
+            session: false,
+            timezone: Expr::Value(Value::SingleQuotedString("Europe/Rome".to_string())),
+        }
+    );
+
+    let stmt = pg().verified_stmt("SET TIME ZONE LOCAL");
+    assert_eq!(
+        stmt,
+        Statement::SetTimeZone {
+            local: false,
+            session: false,
+            timezone: Expr::Identifier(Ident {
+                value: "LOCAL".to_string(),
+                quote_style: None,
+            }),
+        }
+    );
+}
+
 #[test]
 fn parse_show() {
     let stmt = pg_and_generic().verified_stmt("SHOW a a");