With Recursive

core/src/main/antlr4/com/databricks/labs/remorph/parsers/snowflake/SnowflakeParser.g4

@@ -3329,14 +3329,11 @@ switchSection: WHEN expr THEN expr
 queryStatement: withExpression? selectStatement setOperators*
     ;
 
-withExpression: WITH commonTableExpression (COMMA commonTableExpression)*
+withExpression: WITH RECURSIVE? commonTableExpression (COMMA commonTableExpression)*
     ;
 
 commonTableExpression
-    : tableName = id (L_PAREN columns += id (COMMA columns += id)* R_PAREN)? AS L_PAREN (
-        (selectStatement setOperators*)
-        | expr
-    ) R_PAREN
+    : tableName = id (L_PAREN columnList R_PAREN)? AS L_PAREN ((selectStatement setOperators*) | expr) R_PAREN
     ;
 
 selectStatement

core/src/main/scala/com/databricks/labs/remorph/parsers/snowflake/SnowflakeAstBuilder.scala

@@ -90,9 +90,19 @@ class SnowflakeAstBuilder(override val vc: SnowflakeVisitorCoordinator)
     errorCheck(ctx) match {
       case Some(errorResult) => errorResult
       case None =>
-        val ctes = vc.relationBuilder.visitMany(ctx.commonTableExpression())
-        ir.WithCTE(ctes, relation)
+        if (ctx.RECURSIVE() == null) {
+          val ctes = vc.relationBuilder.visitMany(ctx.commonTableExpression())
+          ir.WithCTE(ctes, relation)
+        } else {
+          ir.UnresolvedCommand(
+            ruleText = contextText(ctx),
+            message = "*** WITH RECURSIVE IS NOT SUPPORTED ***",
+            ruleName = vc.ruleName(ctx),
+            tokenName = Some(tokenName(ctx.getStart)))
+        }
+
     }
+
   }
 
   private def buildSetOperator(left: ir.LogicalPlan, ctx: SetOperatorsContext): ir.LogicalPlan = {

core/src/main/scala/com/databricks/labs/remorph/parsers/snowflake/SnowflakeRelationBuilder.scala

@@ -328,9 +328,14 @@ class SnowflakeRelationBuilder(override val vc: SnowflakeVisitorCoordinator)
     case Some(errorResult) => errorResult
     case None =>
       val tableName = vc.expressionBuilder.buildId(ctx.tableName)
-      val columns = ctx.columns.asScala.map(vc.expressionBuilder.buildId)
+      val columns = ctx.columnList() match {
+        case null => Seq.empty[ir.Id]
+        case c => c.columnName().asScala.flatMap(_.id.asScala.map(vc.expressionBuilder.buildId))
+      }
+
       val query = ctx.selectStatement().accept(this)
       ir.SubqueryAlias(query, tableName, columns)
+
   }
 
   private def buildNum(ctx: NumContext): BigDecimal = {

tests/resources/functional/snowflake/core_engine/test_cte/cte_simple.sql

@@ -0,0 +1,16 @@
+-- snowflake sql:
+WITH employee_hierarchy AS (
+    SELECT
+        employee_id,
+        manager_id,
+        employee_name
+    FROM
+        employees
+    WHERE
+        manager_id IS NULL
+)
+SELECT *
+FROM employee_hierarchy;
+
+-- databricks sql:
+WITH employee_hierarchy AS (SELECT employee_id, manager_id, employee_name FROM employees WHERE manager_id IS NULL) SELECT * FROM employee_hierarchy;

tests/resources/functional/snowflake/core_engine/test_cte/recursive_cte.sql

@@ -0,0 +1,52 @@
+-- snowflake sql:
+WITH RECURSIVE employee_hierarchy AS (
+    SELECT
+        employee_id,
+        manager_id,
+        employee_name,
+        1 AS level
+    FROM
+        employees
+    WHERE
+        manager_id IS NULL
+    UNION ALL
+    SELECT
+        e.employee_id,
+        e.manager_id,
+        e.employee_name,
+        eh.level + 1 AS level
+    FROM
+        employees e
+    INNER JOIN
+        employee_hierarchy eh ON e.manager_id = eh.employee_id
+)
+SELECT *
+FROM employee_hierarchy
+ORDER BY level, employee_id;
+
+-- databricks sql:
+/* The following issues were detected:
+
+   *** WITH RECURSIVE IS NOT SUPPORTED ***
+    WITH RECURSIVE employee_hierarchy AS (
+        SELECT
+            employee_id,
+            manager_id,
+            employee_name,
+            1 AS level
+        FROM
+            employees
+        WHERE
+            manager_id IS NULL
+        UNION ALL
+        SELECT
+            e.employee_id,
+            e.manager_id,
+            e.employee_name,
+            eh.level + 1 AS level
+        FROM
+            employees e
+        INNER JOIN
+            employee_hierarchy eh ON e.manager_id = eh.employee_id
+    )
+ */