Returns the tree node at the specified number, used primarily for interactive debugging. Numbers for each node can be found in the numberedTreeString.

Note that this cannot return BaseType because logical plan's plan node might return physical plan for innerChildren, e.g. in-memory relation logical plan node has a reference to the physical plan node it is referencing.

Returns a string representing the arguments to this node, minus any children

Returns a 'scala code' representation of this TreeNode and its children. Intended for use when debugging where the prettier toString function is obfuscating the actual structure. In the case of 'pure' TreeNodes that only contain primitives and other TreeNodes, the result can be pasted in the REPL to build an equivalent Tree.

Name of the function for this expression on a CalendarInterval type.

Returns an expression where a best effort attempt has been made to transform this in a way that preserves the result but removes cosmetic variations (case sensitivity, ordering for commutative operations, etc.).

deterministic expressions where this.canonicalized == other.canonicalized will always evaluate to the same result.

The process of canonicalization is a one pass, bottum-up expression tree computation based on canonicalizing children before canonicalizing the current node. There is one exception though, as adjacent, same class CommutativeExpressions canonicalazion happens in a way that calling canonicalized on the root:

1. Gathers and canonicalizes the non-commutative (or commutative but not same class) child expressions of the adjacent expressions. 2. Reorder the canonicalized child expressions by their hashcode. This means that the lazy cannonicalized is called and computed only on the root of the adjacent expressions.

Checks the input data types, returns TypeCheckResult.success if it's valid, or returns a TypeCheckResult with an error message if invalid. Note: it's not valid to call this method until childrenResolved == true.

Returns true if all the children of this expression have been resolved to a specific schema and false if any still contains any unresolved placeholders.

Returns a Seq containing the result of applying a partial function to all elements in this tree on which the function is defined.

Finds and returns the first TreeNode of the tree for which the given partial function is defined (pre-order), and applies the partial function to it.

Returns a Seq containing the leaves in this tree.

Returns true if the expression can be folded without relying on external context, such as current time zone, session configurations, or catalogs.

When an expression is context-independent foldable, it can be safely evaluated during DDL operations like creating tables, views, or constraints. This allows systems to store the computed value rather than the expression itself, improving both simplicity and performance.

Default is false to ensure explicit marking of context independence.

Returns the DataType of the result of evaluating this expression. It is invalid to query the dataType of an unresolved expression (i.e., when resolved == false).

Name of the function for this expression on a Decimal type.

Short hand for generating binary evaluation code. If either of the sub-expressions is null, the result of this computation is assumed to be null.

Returns true when the current expression always return the same result for fixed inputs from children. The non-deterministic expressions should not change in number and order. They should not be evaluated during the query planning.

Note that this means that an expression should be considered as non-deterministic if: - it relies on some mutable internal state, or - it relies on some implicit input that is not part of the children expression list. - it has non-deterministic child or children. - it assumes the input satisfies some certain condition via the child operator.

An example would be SparkPartitionID that relies on the partition id returned by TaskContext. By default leaf expressions are deterministic as Nil.forall(_.deterministic) returns true.

Special case handling due to division/remainder by 0 => null or ArithmeticException.

Returns Java source code that can be compiled to evaluate this expression. The default behavior is to call the eval method of the expression. Concrete expression implementations should override this to do actual code generation.

Default behavior of evaluation according to the default nullability of BinaryExpression. If subclass of BinaryExpression override nullable, probably should also override this.

Test whether there is TreeNode satisfies the conditions specified in f. The condition is recursively applied to this node and all of its children (pre-order).

Faster version of equality which short-circuits when two treeNodes are the same instance. We don't just override Object.equals, as doing so prevents the scala compiler from generating case class equals methods

Find the first TreeNode that satisfies the condition specified by f. The condition is recursively applied to this node and all of its children (pre-order).

Returns a Seq by applying a function to all nodes in this tree and using the elements of the resulting collections.

Returns true when an expression is a candidate for static evaluation before the query is executed. A typical use case: org.apache.spark.sql.catalyst.optimizer.ConstantFolding

The following conditions are used to determine suitability for constant folding:

• A Coalesce is foldable if all of its children are foldable
• A BinaryExpression is foldable if its both left and right child are foldable
• A Not, IsNull, or IsNotNull is foldable if its child is foldable
• A Literal is foldable
• A Cast or UnaryMinus is foldable if its child is foldable

Runs the given function on this node and then recursively on children.

Runs the given function recursively on children then on this node.

Returns a copy of this expression where all stateful expressions are replaced with fresh uninitialized copies. If the expression contains no stateful expressions then the original expression is returned.

Returns an ExprCode, that contains the Java source code to generate the result of evaluating the expression on an input row.

Appends the string representation of this node and its children to the given Writer.

The i-th element in lastChildren indicates whether the ancestor of the current node at depth i + 1 is the last child of its own parent node. The depth of the root node is 0, and lastChildren for the root node should be empty.

Note that this traversal (numbering) order must be the same as getNodeNumbered.

Default tree pattern for a TreeNode.

All the nodes that should be shown as a inner nested tree of this node. For example, this can be used to show sub-queries.

Expected input type from both left/right child expressions, similar to the ImplicitCastInputTypes trait.

Expected input types from child expressions. The i-th position in the returned seq indicates the type requirement for the i-th child.

The possible values at each position are: 1. a specific data type, e.g. LongType, StringType. 2. a non-leaf abstract data type, e.g. NumericType, IntegralType, FractionalType.

Whether this TreeNode and its subtree have been marked as ineffective for the rule with id ruleId.

Returns a copy of this node with the children replaced. TODO: Validate somewhere (in debug mode?) that children are ordered correctly.

Creates a copy of this type of tree node after a transformation. Must be overridden by child classes that have constructor arguments that are not present in the productIterator.

Returns a Seq containing the result of applying the given function to each node in this tree in a preorder traversal.

Efficient alternative to productIterator.map(f).toArray.

Mark that a rule (with id ruleId) is ineffective for this TreeNode and its subtree.

Returns alternative copies of this node where rule has been recursively applied to it and all of its children (pre-order).

Returns alternative copies of this node where rule has been recursively applied to it and all of its children (pre-order).

As it is very easy to generate enormous number of alternatives when the input tree is huge or when the rule returns many alternatives for many nodes, this function returns the alternatives as a lazy LazyList to be able to limit the number of alternatives generated at the caller side as needed.

The purpose of this function to access the returned alternatives by the rule only if they are needed so the rule can return a LazyList whose elements are also lazily calculated. E.g. multiTransform* calls can be nested with the help of MultiTransform.generateCartesianProduct().

The rule should not apply or can return a one element Seq of original node to indicate that the original node without any transformation is a valid alternative.

The rule can return Seq.empty to indicate that the original node should be pruned. In this case multiTransform() returns an empty LazyList.

Please consider the following examples of input.multiTransformDown(rule):

We have an input expression: Add(a, b)

1. We have a simple rule: a => Seq(1, 2) b => Seq(10, 20) Add(a, b) => Seq(11, 12, 21, 22)

The output is: LazyList(11, 12, 21, 22)

2. In the previous example if we want to generate alternatives of a and b too then we need to explicitly add the original Add(a, b) expression to the rule: a => Seq(1, 2) b => Seq(10, 20) Add(a, b) => Seq(11, 12, 21, 22, Add(a, b))

The output is: LazyList(11, 12, 21, 22, Add(1, 10), Add(2, 10), Add(1, 20), Add(2, 20))

Returns the name of this type of TreeNode. Defaults to the class name. Note that we remove the "Exec" suffix for physical operators here.

When an expression inherits this, meaning the expression is null intolerant (i.e. any null input will result in null output). We will use this information during constructing IsNotNull constraints.

Short hand for generating binary evaluation code. If either of the sub-expressions is null, the result of this computation is assumed to be null.

Called by default eval implementation. If subclass of BinaryExpression keep the default nullability, they can override this method to save null-check code. If we need full control of evaluation process, we should override eval.

Returns a string representation of the nodes in this tree, where each operator is numbered. The numbers can be used with TreeNode.apply to easily access specific subtrees.

The numbers are based on depth-first traversal of the tree (with innerChildren traversed first before children).

Args to the constructor that should be copied, but not transformed. These are appended to the transformed args automatically by makeCopy

Returns the tree node at the specified number, used primarily for interactive debugging. Numbers for each node can be found in the numberedTreeString.

This is a variant of apply that returns the node as BaseType (if the type matches).

Returns a user-facing string representation of this expression's name. This should usually match the name of the function in SQL.

Returns true if this expression and all its children have been resolved to a specific schema and input data types checking passed, and false if it still contains any unresolved placeholders or has data types mismatch. Implementations of expressions should override this if the resolution of this type of expression involves more than just the resolution of its children and type checking.

Returns true when two expressions will always compute the same result, even if they differ cosmetically (i.e. capitalization of names in attributes may be different).

See Expression#canonicalized for more details.

Returns a hashCode for the calculation performed by this expression. Unlike the standard hashCode, an attempt has been made to eliminate cosmetic differences.

See Expression#canonicalized for more details.

ONE line description of this node.

ONE line description of this node containing the node identifier.

Returns SQL representation of this expression. For expressions extending NonSQLExpression, this method may return an arbitrary user facing string.

Returns true if the expression contains mutable state.

A stateful expression should never be evaluated multiple times for a single row. This should only be a problem for interpreted execution. This can be prevented by creating fresh copies of the stateful expression before execution. A common example to trigger this issue:

val rand = functions.rand()
df.select(rand, rand) // These 2 rand should not share a state.

The arguments that should be included in the arg string. Defaults to the productIterator.

Returns true if the expression could potentially throw an exception when evaluated.

Returns a copy of this node where rule has been recursively applied to the tree. When rule does not apply to a given node it is left unchanged. Users should not expect a specific directionality. If a specific directionality is needed, transformDown or transformUp should be used.

Returns a copy of this node where rule has been recursively applied to it and all of its children (pre-order). When rule does not apply to a given node it is left unchanged.

Returns a copy of this node where rule has been recursively applied to it and all of its children (pre-order). When rule does not apply to a given node it is left unchanged.

Returns a copy of this node where rule has been recursively applied first to all of its children and then itself (post-order). When rule does not apply to a given node, it is left unchanged.

Returns a copy of this node where rule has been recursively applied first to all of its children and then itself (post-order). When rule does not apply to a given node, it is left unchanged.

Returns a copy of this node where rule has been recursively applied first to all of its children and then itself (post-order). When rule does not apply to a given node, it is left unchanged.

Returns a copy of this node where rule has been recursively applied to the tree. When rule does not apply to a given node it is left unchanged. Users should not expect a specific directionality. If a specific directionality is needed, transformDown or transformUp should be used.

Returns a string representation of the nodes in this tree

For child classes to validate nodePatterns.

ONE line description of this node with more information

ONE line description of this node with some suffix information

The default process of canonicalization. It is a one pass, bottum-up expression tree computation based oncanonicalizing children before canonicalizing the current node.