Add BigQuery CREATE EXTERNAL TABLE WITH PARTITION COLUMNS parsing support

crates/polyglot-sql/src/builder.rs

@@ -1617,6 +1617,8 @@ impl SelectBuilder {
             copy_grants: false,
             using_template: None,
             rollup: None,
+            with_partition_columns: vec![],
+            with_connection: None,
         }))
     }
 

crates/polyglot-sql/src/dialects/mod.rs

@@ -26107,6 +26107,8 @@ impl Dialect {
                             copy_grants: false,
                             using_template: None,
                             rollup: None,
+                            with_partition_columns: Vec::new(),
+                            with_connection: None,
                         };
                         return Expression::CreateTable(Box::new(ct));
                     }

crates/polyglot-sql/src/expressions.rs

@@ -5841,6 +5841,15 @@ pub struct CreateTable {
     /// StarRocks: ROLLUP (r1(col1, col2), r2(col1))
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub rollup: Option<RollupProperty>,
+    /// WITH PARTITION COLUMNS (col_name col_type, ...) — currently used by BigQuery
+    /// for hive-partitioned external tables. Not dialect-prefixed since the syntax
+    /// could appear in other engines.
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub with_partition_columns: Vec<ColumnDef>,
+    /// WITH CONNECTION `project.region.connection` — currently used by BigQuery
+    /// for external tables that reference a Cloud Resource connection.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub with_connection: Option<TableRef>,
 }
 
 /// Teradata index specification for CREATE TABLE
@@ -5907,6 +5916,8 @@ impl CreateTable {
             copy_grants: false,
             using_template: None,
             rollup: None,
+            with_partition_columns: Vec::new(),
+            with_connection: None,
         }
     }
 }

crates/polyglot-sql/src/generator.rs

@@ -7493,6 +7493,51 @@ impl Generator {
             self.generate_expression(&on_prop.this)?;
         }
 
+        // BigQuery: WITH PARTITION COLUMNS (col_name col_type, ...)
+        if !ct.with_partition_columns.is_empty() {
+            if self.config.pretty {
+                self.write_newline();
+            } else {
+                self.write_space();
+            }
+            self.write_keyword("WITH PARTITION COLUMNS");
+            self.write(" (");
+            if self.config.pretty {
+                self.write_newline();
+                self.indent_level += 1;
+                for (i, col) in ct.with_partition_columns.iter().enumerate() {
+                    if i > 0 {
+                        self.write(",");
+                        self.write_newline();
+                    }
+                    self.write_indent();
+                    self.generate_column_def(col)?;
+                }
+                self.indent_level -= 1;
+                self.write_newline();
+            } else {
+                for (i, col) in ct.with_partition_columns.iter().enumerate() {
+                    if i > 0 {
+                        self.write(", ");
+                    }
+                    self.generate_column_def(col)?;
+                }
+            }
+            self.write(")");
+        }
+
+        // BigQuery: WITH CONNECTION `project.region.connection`
+        if let Some(ref conn) = ct.with_connection {
+            if self.config.pretty {
+                self.write_newline();
+            } else {
+                self.write_space();
+            }
+            self.write_keyword("WITH CONNECTION");
+            self.write_space();
+            self.generate_table(conn)?;
+        }
+
         // Output SchemaCommentProperty BEFORE WITH properties (Presto/Hive/Spark style)
         // For ClickHouse, SchemaCommentProperty goes after AS SELECT, handled later
         if !is_clickhouse {