Add support for Postgres LOAD extension expr

Author: wugeer

src/dialect/postgresql.rs

@@ -214,6 +214,11 @@ impl Dialect for PostgreSqlDialect {
     fn supports_comment_on(&self) -> bool {
         true
     }
+
+    /// See <https://www.postgresql.org/docs/current/sql-load.html>
+    fn supports_load_extension(&self) -> bool {
+        true
+    }
 }
 
 pub fn parse_create(parser: &mut Parser) -> Option<Result<Statement, ParserError>> {

tests/sqlparser_common.rs

@@ -11895,6 +11895,56 @@ fn parse_load_data() {
     );
 }
 
+#[test]
+fn test_load_extension() {
+    let dialects = all_dialects_where(|d| d.supports_load_extension());
+    let only_supports_load_data_dialects =
+        all_dialects_where(|d| !d.supports_load_extension() && d.supports_load_data());
+    let not_supports_load_dialects =
+        all_dialects_where(|d| !d.supports_load_data() && !d.supports_load_extension());
+    let sql = "LOAD my_extension";
+
+    match dialects.verified_stmt(sql) {
+        Statement::Load { extension_name } => {
+            assert_eq!(Ident::new("my_extension"), extension_name);
+        }
+        _ => unreachable!(),
+    };
+
+    assert_eq!(
+        only_supports_load_data_dialects
+            .parse_sql_statements(sql)
+            .unwrap_err(),
+        ParserError::ParserError(
+            "Expected: `DATA` or an extension name after `LOAD`, found: my_extension".to_string()
+        )
+    );
+
+    assert_eq!(
+        not_supports_load_dialects
+            .parse_sql_statements(sql)
+            .unwrap_err(),
+        ParserError::ParserError(
+            "Expected: `DATA` or an extension name after `LOAD`, found: my_extension".to_string()
+        )
+    );
+
+    let sql = "LOAD 'filename'";
+
+    match dialects.verified_stmt(sql) {
+        Statement::Load { extension_name } => {
+            assert_eq!(
+                Ident {
+                    value: "filename".to_string(),
+                    quote_style: Some('\'')
+                },
+                extension_name
+            );
+        }
+        _ => unreachable!(),
+    };
+}
+
 #[test]
 fn test_select_top() {
     let dialects = all_dialects_where(|d| d.supports_top_before_distinct());

tests/sqlparser_duckdb.rs

@@ -359,20 +359,6 @@ fn test_duckdb_install() {
     );
 }
 
-#[test]
-fn test_duckdb_load_extension() {
-    let stmt = duckdb().verified_stmt("LOAD my_extension");
-    assert_eq!(
-        Statement::Load {
-            extension_name: Ident {
-                value: "my_extension".to_string(),
-                quote_style: None
-            }
-        },
-        stmt
-    );
-}
-
 #[test]
 fn test_duckdb_struct_literal() {
     //struct literal syntax https://duckdb.org/docs/sql/data_types/struct#creating-structs