[FEAT]: Sql joins with duplicate cols

src/daft-logical-plan/src/builder.rs

@@ -443,6 +443,7 @@ impl LogicalPlanBuilder {
         join_strategy: Option<JoinStrategy>,
         join_suffix: Option<&str>,
         join_prefix: Option<&str>,
+        keep_join_keys: bool,
     ) -> DaftResult<Self> {
         self.join_with_null_safe_equal(
             right,
@@ -453,6 +454,7 @@ impl LogicalPlanBuilder {
             join_strategy,
             join_suffix,
             join_prefix,
+            keep_join_keys,
         )
     }
 
@@ -467,6 +469,7 @@ impl LogicalPlanBuilder {
         join_strategy: Option<JoinStrategy>,
         join_suffix: Option<&str>,
         join_prefix: Option<&str>,
+        keep_join_keys: bool,
     ) -> DaftResult<Self> {
         let logical_plan: LogicalPlan = ops::Join::try_new(
             self.plan.clone(),
@@ -478,6 +481,7 @@ impl LogicalPlanBuilder {
             join_strategy,
             join_suffix,
             join_prefix,
+            keep_join_keys,
         )?
         .into();
         Ok(self.with_new_plan(logical_plan))
@@ -497,6 +501,7 @@ impl LogicalPlanBuilder {
             None,
             join_suffix,
             join_prefix,
+            false, // no join keys to keep
         )
     }
 
@@ -937,6 +942,7 @@ impl PyLogicalPlanBuilder {
                 join_strategy,
                 join_suffix,
                 join_prefix,
+                false, // dataframes do not keep the join keys when joining
             )?
             .into())
     }

src/daft-logical-plan/src/display.rs

@@ -111,6 +111,7 @@ mod test {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(col("first_name").eq(lit("hello")))?
             .select(vec![col("first_name")])?
@@ -185,6 +186,7 @@ Project1 --> Limit0
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(col("first_name").eq(lit("hello")))?
             .select(vec![col("first_name")])?

src/daft-logical-plan/src/logical_plan.rs

@@ -273,7 +273,8 @@ impl LogicalPlan {
                     *join_type,
                     *join_strategy,
                     None,  // The suffix is already eagerly computed in the constructor
-                    None // the prefix is already eagerly computed in the constructor
+                    None,  // the prefix is already eagerly computed in the constructor
+                    false // this is already eagerly computed in the constructor
                 ).unwrap()),
                 _ => panic!("Logical op {} has one input, but got two", self),
             },

src/daft-logical-plan/src/ops/join.rs

@@ -60,6 +60,11 @@ impl Join {
         join_strategy: Option<JoinStrategy>,
         join_suffix: Option<&str>,
         join_prefix: Option<&str>,
+        // if true, then duplicate column names will be kept
+        // ex: select * from a left join b on a.id = b.id
+        // if true, then the resulting schema will have two columns named id (id, and b.id)
+        // In SQL the join column is always kept, while in dataframes it is not
+        keep_join_keys: bool,
     ) -> logical_plan::Result<Self> {
         let (left_on, _) = resolve_exprs(left_on, &left.schema(), false).context(CreationSnafu)?;
         let (right_on, _) =
@@ -136,19 +141,27 @@ impl Join {
             let right_rename_mapping: HashMap<_, _> = right_names
                 .iter()
                 .filter_map(|name| {
-                    if !names_so_far.contains(name) || common_join_keys.contains(name) {
+                    if !names_so_far.contains(name)
+                        || (common_join_keys.contains(name) && !keep_join_keys)
+                    {
                         None
                     } else {
                         let mut new_name = name.clone();
                         while names_so_far.contains(&new_name) {
-                            if let Some(prefix) = join_prefix {
-                                new_name = format!("{}{}", prefix, new_name);
-                            } else if join_suffix.is_none() {
-                                new_name = format!("right.{}", new_name);
-                            }
-                            if let Some(suffix) = join_suffix {
-                                new_name = format!("{}{}", new_name, suffix);
-                            }
+                            new_name = match (join_prefix, join_suffix) {
+                                (Some(prefix), Some(suffix)) => {
+                                    format!("{}{}{}", prefix, new_name, suffix)
+                                }
+                                (Some(prefix), None) => {
+                                    format!("{}{}", prefix, new_name)
+                                }
+                                (None, Some(suffix)) => {
+                                    format!("{}{}", new_name, suffix)
+                                }
+                                (None, None) => {
+                                    format!("right.{}", new_name)
+                                }
+                            };
                         }
                         names_so_far.insert(new_name.clone());
 
@@ -253,6 +266,7 @@ impl Join {
                     }
                     _ => {
                         let unique_id = Uuid::new_v4().to_string();
+
                         let renamed_left_expr =
                             left_expr.alias(format!("{}_{}", left_expr.name(), unique_id));
                         let renamed_right_expr =

src/daft-logical-plan/src/optimization/rules/eliminate_cross_join.rs

@@ -524,6 +524,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .build();
 
@@ -554,6 +555,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(col("a").eq(col("right.a")).or(col("right.b").eq(col("a"))))?
             .build();
@@ -588,6 +590,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(expr2.and(expr4))?
             .build();
@@ -622,6 +625,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(expr2.or(expr4))?
             .build();
@@ -682,6 +686,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(col("t2.c").lt(lit(15u32)).or(col("t2.c").eq(lit(688u32))))?
             .build();
@@ -699,6 +704,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(
                 col("t4.c")
@@ -724,6 +730,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(col("t4.c").lt(lit(15u32)).or(col("t4.c").eq(lit(688u32))))?
             .build();

src/daft-logical-plan/src/optimization/rules/push_down_filter.rs

@@ -683,6 +683,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(pred.clone())?
             .build();
@@ -704,6 +705,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .build();
         assert_optimized_plan_eq(plan, expected)?;
@@ -747,6 +749,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(pred.clone())?
             .build();
@@ -768,6 +771,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .build();
         assert_optimized_plan_eq(plan, expected)?;
@@ -824,6 +828,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(pred.clone())?
             .build();
@@ -853,6 +858,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .build();
         assert_optimized_plan_eq(plan, expected)?;
@@ -892,6 +898,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(pred)?
             .build();
@@ -934,6 +941,7 @@ mod tests {
                 None,
                 None,
                 None,
+                false,
             )?
             .filter(pred)?
             .build();

src/daft-physical-plan/src/physical_planner/translate.rs

@@ -1210,6 +1210,7 @@ mod tests {
                 Some(JoinStrategy::Hash),
                 None,
                 None,
+                false,
             )?
             .build();
         logical_to_physical(logical_plan, cfg)

src/daft-sql/src/lib.rs

@@ -271,7 +271,8 @@ mod tests {
                 JoinType::Inner,
                 None,
                 None,
-                None,
+                Some("tbl3."),
+                true,
             )?
             .select(vec![col("*")])?
             .build();