feat: Support SHOW COLLATION (#11)

Author: MazterQyou

src/ast/mod.rs

@@ -890,6 +890,10 @@ pub enum Statement {
         db_name: Option<Ident>,
         filter: Option<ShowStatementFilter>,
     },
+    /// SHOW COLLATION
+    ///
+    /// Note: this is a MySQL-specific statement.
+    ShowCollation { filter: Option<ShowStatementFilter> },
     /// `{ BEGIN [ TRANSACTION | WORK ] | START TRANSACTION } ...`
     StartTransaction { modes: Vec<TransactionMode> },
     /// `SET TRANSACTION ...`
@@ -1602,6 +1606,13 @@ impl fmt::Display for Statement {
                 }
                 Ok(())
             }
+            Statement::ShowCollation { filter } => {
+                write!(f, "SHOW COLLATION")?;
+                if let Some(filter) = filter {
+                    write!(f, " {}", filter)?;
+                }
+                Ok(())
+            }
             Statement::StartTransaction { modes } => {
                 write!(f, "START TRANSACTION")?;
                 if !modes.is_empty() {

src/keywords.rs

@@ -128,6 +128,7 @@ define_keywords!(
     CLUSTER,
     COALESCE,
     COLLATE,
+    COLLATION,
     COLLECT,
     COLUMN,
     COLUMNS,

src/parser.rs

@@ -3283,6 +3283,8 @@ impl<'a> Parser<'a> {
             Err(ParserError::ParserError(
                 "EXTENDED/FULL are not supported with this type of SHOW query".to_string(),
             ))
+        } else if self.parse_keyword(Keyword::COLLATION) {
+            Ok(self.parse_show_collation()?)
         } else if self.parse_one_of_keywords(&[Keyword::CREATE]).is_some() {
             Ok(self.parse_show_create()?)
         } else if self.parse_one_of_keywords(&[Keyword::VARIABLES]).is_some() {
@@ -3362,6 +3364,11 @@ impl<'a> Parser<'a> {
         })
     }
 
+    fn parse_show_collation(&mut self) -> Result<Statement, ParserError> {
+        let filter = self.parse_show_statement_filter()?;
+        Ok(Statement::ShowCollation { filter })
+    }
+
     fn parse_show_statement_filter(&mut self) -> Result<Option<ShowStatementFilter>, ParserError> {
         if self.parse_keyword(Keyword::LIKE) {
             Ok(Some(ShowStatementFilter::Like(

tests/sqlparser_mysql.rs

@@ -162,6 +162,28 @@ fn parse_show_tables() {
     mysql_and_generic().one_statement_parses_to("SHOW TABLES IN mydb", "SHOW TABLES FROM mydb");
 }
 
+#[test]
+fn parse_show_collation() {
+    assert_eq!(
+        mysql_and_generic().verified_stmt("SHOW COLLATION"),
+        Statement::ShowCollation { filter: None }
+    );
+    assert_eq!(
+        mysql_and_generic().verified_stmt("SHOW COLLATION LIKE 'pattern'"),
+        Statement::ShowCollation {
+            filter: Some(ShowStatementFilter::Like("pattern".into())),
+        }
+    );
+    assert_eq!(
+        mysql_and_generic().verified_stmt("SHOW COLLATION WHERE 1 = 2"),
+        Statement::ShowCollation {
+            filter: Some(ShowStatementFilter::Where(
+                mysql_and_generic().verified_expr("1 = 2")
+            )),
+        }
+    );
+}
+
 #[test]
 fn parse_show_create() {
     let obj_name = ObjectName(vec![Ident::new("myident")]);