sqlglot.optimizer.canonicalize
1from __future__ import annotations 2 3import itertools 4 5from sqlglot import exp 6 7 8def canonicalize(expression: exp.Expression) -> exp.Expression: 9 """Converts a sql expression into a standard form. 10 11 This method relies on annotate_types because many of the 12 conversions rely on type inference. 13 14 Args: 15 expression: The expression to canonicalize. 16 """ 17 exp.replace_children(expression, canonicalize) 18 19 expression = add_text_to_concat(expression) 20 expression = replace_date_funcs(expression) 21 expression = coerce_type(expression) 22 expression = remove_redundant_casts(expression) 23 expression = ensure_bool_predicates(expression) 24 expression = remove_ascending_order(expression) 25 26 return expression 27 28 29def add_text_to_concat(node: exp.Expression) -> exp.Expression: 30 if isinstance(node, exp.Add) and node.type and node.type.this in exp.DataType.TEXT_TYPES: 31 node = exp.Concat(expressions=[node.left, node.right]) 32 return node 33 34 35def replace_date_funcs(node: exp.Expression) -> exp.Expression: 36 if isinstance(node, exp.Date) and not node.expressions and not node.args.get("zone"): 37 return exp.cast(node.this, to=exp.DataType.Type.DATE) 38 if isinstance(node, exp.Timestamp) and not node.expression: 39 return exp.cast(node.this, to=exp.DataType.Type.TIMESTAMP) 40 return node 41 42 43def coerce_type(node: exp.Expression) -> exp.Expression: 44 if isinstance(node, exp.Binary): 45 _coerce_date(node.left, node.right) 46 elif isinstance(node, exp.Between): 47 _coerce_date(node.this, node.args["low"]) 48 elif isinstance(node, exp.Extract): 49 if node.expression.type.this not in exp.DataType.TEMPORAL_TYPES: 50 _replace_cast(node.expression, "datetime") 51 return node 52 53 54def remove_redundant_casts(expression: exp.Expression) -> exp.Expression: 55 if ( 56 isinstance(expression, exp.Cast) 57 and expression.to.type 58 and expression.this.type 59 and expression.to.type.this == expression.this.type.this 60 ): 61 return expression.this 62 return expression 63 64 65def ensure_bool_predicates(expression: exp.Expression) -> exp.Expression: 66 if isinstance(expression, exp.Connector): 67 _replace_int_predicate(expression.left) 68 _replace_int_predicate(expression.right) 69 70 elif isinstance(expression, (exp.Where, exp.Having)): 71 _replace_int_predicate(expression.this) 72 73 return expression 74 75 76def remove_ascending_order(expression: exp.Expression) -> exp.Expression: 77 if isinstance(expression, exp.Ordered) and expression.args.get("desc") is False: 78 # Convert ORDER BY a ASC to ORDER BY a 79 expression.set("desc", None) 80 81 return expression 82 83 84def _coerce_date(a: exp.Expression, b: exp.Expression) -> None: 85 for a, b in itertools.permutations([a, b]): 86 if ( 87 a.type 88 and a.type.this == exp.DataType.Type.DATE 89 and b.type 90 and b.type.this not in (exp.DataType.Type.DATE, exp.DataType.Type.INTERVAL) 91 ): 92 _replace_cast(b, "date") 93 94 95def _replace_cast(node: exp.Expression, to: str) -> None: 96 node.replace(exp.cast(node.copy(), to=to)) 97 98 99def _replace_int_predicate(expression: exp.Expression) -> None: 100 if expression.type and expression.type.this in exp.DataType.INTEGER_TYPES: 101 expression.replace(exp.NEQ(this=expression.copy(), expression=exp.Literal.number(0)))
9def canonicalize(expression: exp.Expression) -> exp.Expression: 10 """Converts a sql expression into a standard form. 11 12 This method relies on annotate_types because many of the 13 conversions rely on type inference. 14 15 Args: 16 expression: The expression to canonicalize. 17 """ 18 exp.replace_children(expression, canonicalize) 19 20 expression = add_text_to_concat(expression) 21 expression = replace_date_funcs(expression) 22 expression = coerce_type(expression) 23 expression = remove_redundant_casts(expression) 24 expression = ensure_bool_predicates(expression) 25 expression = remove_ascending_order(expression) 26 27 return expression
Converts a sql expression into a standard form.
This method relies on annotate_types because many of the conversions rely on type inference.
Arguments:
- expression: The expression to canonicalize.
36def replace_date_funcs(node: exp.Expression) -> exp.Expression: 37 if isinstance(node, exp.Date) and not node.expressions and not node.args.get("zone"): 38 return exp.cast(node.this, to=exp.DataType.Type.DATE) 39 if isinstance(node, exp.Timestamp) and not node.expression: 40 return exp.cast(node.this, to=exp.DataType.Type.TIMESTAMP) 41 return node
44def coerce_type(node: exp.Expression) -> exp.Expression: 45 if isinstance(node, exp.Binary): 46 _coerce_date(node.left, node.right) 47 elif isinstance(node, exp.Between): 48 _coerce_date(node.this, node.args["low"]) 49 elif isinstance(node, exp.Extract): 50 if node.expression.type.this not in exp.DataType.TEMPORAL_TYPES: 51 _replace_cast(node.expression, "datetime") 52 return node
def
remove_redundant_casts( expression: sqlglot.expressions.Expression) -> sqlglot.expressions.Expression:
def
ensure_bool_predicates( expression: sqlglot.expressions.Expression) -> sqlglot.expressions.Expression:
66def ensure_bool_predicates(expression: exp.Expression) -> exp.Expression: 67 if isinstance(expression, exp.Connector): 68 _replace_int_predicate(expression.left) 69 _replace_int_predicate(expression.right) 70 71 elif isinstance(expression, (exp.Where, exp.Having)): 72 _replace_int_predicate(expression.this) 73 74 return expression
def
remove_ascending_order( expression: sqlglot.expressions.Expression) -> sqlglot.expressions.Expression: