sqlglot.optimizer.canonicalize
1from __future__ import annotations 2 3import itertools 4import typing as t 5 6from sqlglot import exp 7from sqlglot.helper import is_date_unit, is_iso_date, is_iso_datetime 8 9 10def canonicalize(expression: exp.Expression) -> exp.Expression: 11 """Converts a sql expression into a standard form. 12 13 This method relies on annotate_types because many of the 14 conversions rely on type inference. 15 16 Args: 17 expression: The expression to canonicalize. 18 """ 19 20 def _canonicalize(expression: exp.Expression) -> exp.Expression: 21 expression = add_text_to_concat(expression) 22 expression = replace_date_funcs(expression) 23 expression = coerce_type(expression) 24 expression = remove_redundant_casts(expression) 25 expression = ensure_bools(expression, _replace_int_predicate) 26 expression = remove_ascending_order(expression) 27 return expression 28 29 return exp.replace_tree(expression, _canonicalize) 30 31 32def add_text_to_concat(node: exp.Expression) -> exp.Expression: 33 if isinstance(node, exp.Add) and node.type and node.type.this in exp.DataType.TEXT_TYPES: 34 node = exp.Concat(expressions=[node.left, node.right]) 35 return node 36 37 38def replace_date_funcs(node: exp.Expression) -> exp.Expression: 39 if isinstance(node, exp.Date) and not node.expressions and not node.args.get("zone"): 40 return exp.cast(node.this, to=exp.DataType.Type.DATE) 41 if isinstance(node, exp.Timestamp) and not node.expression: 42 if not node.type: 43 from sqlglot.optimizer.annotate_types import annotate_types 44 45 node = annotate_types(node) 46 return exp.cast(node.this, to=node.type or exp.DataType.Type.TIMESTAMP) 47 48 return node 49 50 51COERCIBLE_DATE_OPS = ( 52 exp.Add, 53 exp.Sub, 54 exp.EQ, 55 exp.NEQ, 56 exp.GT, 57 exp.GTE, 58 exp.LT, 59 exp.LTE, 60 exp.NullSafeEQ, 61 exp.NullSafeNEQ, 62) 63 64 65def coerce_type(node: exp.Expression) -> exp.Expression: 66 if isinstance(node, COERCIBLE_DATE_OPS): 67 _coerce_date(node.left, node.right) 68 elif isinstance(node, exp.Between): 69 _coerce_date(node.this, node.args["low"]) 70 elif isinstance(node, exp.Extract) and not node.expression.type.is_type( 71 *exp.DataType.TEMPORAL_TYPES 72 ): 73 _replace_cast(node.expression, exp.DataType.Type.DATETIME) 74 elif isinstance(node, (exp.DateAdd, exp.DateSub, exp.DateTrunc)): 75 _coerce_timeunit_arg(node.this, node.unit) 76 elif isinstance(node, exp.DateDiff): 77 _coerce_datediff_args(node) 78 79 return node 80 81 82def remove_redundant_casts(expression: exp.Expression) -> exp.Expression: 83 if ( 84 isinstance(expression, exp.Cast) 85 and expression.this.type 86 and expression.to.this == expression.this.type.this 87 ): 88 return expression.this 89 return expression 90 91 92def ensure_bools( 93 expression: exp.Expression, replace_func: t.Callable[[exp.Expression], None] 94) -> exp.Expression: 95 if isinstance(expression, exp.Connector): 96 replace_func(expression.left) 97 replace_func(expression.right) 98 elif isinstance(expression, exp.Not): 99 replace_func(expression.this) 100 # We can't replace num in CASE x WHEN num ..., because it's not the full predicate 101 elif isinstance(expression, exp.If) and not ( 102 isinstance(expression.parent, exp.Case) and expression.parent.this 103 ): 104 replace_func(expression.this) 105 elif isinstance(expression, (exp.Where, exp.Having)): 106 replace_func(expression.this) 107 108 return expression 109 110 111def remove_ascending_order(expression: exp.Expression) -> exp.Expression: 112 if isinstance(expression, exp.Ordered) and expression.args.get("desc") is False: 113 # Convert ORDER BY a ASC to ORDER BY a 114 expression.set("desc", None) 115 116 return expression 117 118 119def _coerce_date(a: exp.Expression, b: exp.Expression) -> None: 120 for a, b in itertools.permutations([a, b]): 121 if isinstance(b, exp.Interval): 122 a = _coerce_timeunit_arg(a, b.unit) 123 if ( 124 a.type 125 and a.type.this == exp.DataType.Type.DATE 126 and b.type 127 and b.type.this 128 not in ( 129 exp.DataType.Type.DATE, 130 exp.DataType.Type.INTERVAL, 131 ) 132 ): 133 _replace_cast(b, exp.DataType.Type.DATE) 134 135 136def _coerce_timeunit_arg(arg: exp.Expression, unit: t.Optional[exp.Expression]) -> exp.Expression: 137 if not arg.type: 138 return arg 139 140 if arg.type.this in exp.DataType.TEXT_TYPES: 141 date_text = arg.name 142 is_iso_date_ = is_iso_date(date_text) 143 144 if is_iso_date_ and is_date_unit(unit): 145 return arg.replace(exp.cast(arg.copy(), to=exp.DataType.Type.DATE)) 146 147 # An ISO date is also an ISO datetime, but not vice versa 148 if is_iso_date_ or is_iso_datetime(date_text): 149 return arg.replace(exp.cast(arg.copy(), to=exp.DataType.Type.DATETIME)) 150 151 elif arg.type.this == exp.DataType.Type.DATE and not is_date_unit(unit): 152 return arg.replace(exp.cast(arg.copy(), to=exp.DataType.Type.DATETIME)) 153 154 return arg 155 156 157def _coerce_datediff_args(node: exp.DateDiff) -> None: 158 for e in (node.this, node.expression): 159 if e.type.this not in exp.DataType.TEMPORAL_TYPES: 160 e.replace(exp.cast(e.copy(), to=exp.DataType.Type.DATETIME)) 161 162 163def _replace_cast(node: exp.Expression, to: exp.DataType.Type) -> None: 164 node.replace(exp.cast(node.copy(), to=to)) 165 166 167# this was originally designed for presto, there is a similar transform for tsql 168# this is different in that it only operates on int types, this is because 169# presto has a boolean type whereas tsql doesn't (people use bits) 170# with y as (select true as x) select x = 0 FROM y -- illegal presto query 171def _replace_int_predicate(expression: exp.Expression) -> None: 172 if isinstance(expression, exp.Coalesce): 173 for child in expression.iter_expressions(): 174 _replace_int_predicate(child) 175 elif expression.type and expression.type.this in exp.DataType.INTEGER_TYPES: 176 expression.replace(expression.neq(0))
11def canonicalize(expression: exp.Expression) -> exp.Expression: 12 """Converts a sql expression into a standard form. 13 14 This method relies on annotate_types because many of the 15 conversions rely on type inference. 16 17 Args: 18 expression: The expression to canonicalize. 19 """ 20 21 def _canonicalize(expression: exp.Expression) -> exp.Expression: 22 expression = add_text_to_concat(expression) 23 expression = replace_date_funcs(expression) 24 expression = coerce_type(expression) 25 expression = remove_redundant_casts(expression) 26 expression = ensure_bools(expression, _replace_int_predicate) 27 expression = remove_ascending_order(expression) 28 return expression 29 30 return exp.replace_tree(expression, _canonicalize)
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.
39def replace_date_funcs(node: exp.Expression) -> exp.Expression: 40 if isinstance(node, exp.Date) and not node.expressions and not node.args.get("zone"): 41 return exp.cast(node.this, to=exp.DataType.Type.DATE) 42 if isinstance(node, exp.Timestamp) and not node.expression: 43 if not node.type: 44 from sqlglot.optimizer.annotate_types import annotate_types 45 46 node = annotate_types(node) 47 return exp.cast(node.this, to=node.type or exp.DataType.Type.TIMESTAMP) 48 49 return node
COERCIBLE_DATE_OPS =
(<class 'sqlglot.expressions.Add'>, <class 'sqlglot.expressions.Sub'>, <class 'sqlglot.expressions.EQ'>, <class 'sqlglot.expressions.NEQ'>, <class 'sqlglot.expressions.GT'>, <class 'sqlglot.expressions.GTE'>, <class 'sqlglot.expressions.LT'>, <class 'sqlglot.expressions.LTE'>, <class 'sqlglot.expressions.NullSafeEQ'>, <class 'sqlglot.expressions.NullSafeNEQ'>)
66def coerce_type(node: exp.Expression) -> exp.Expression: 67 if isinstance(node, COERCIBLE_DATE_OPS): 68 _coerce_date(node.left, node.right) 69 elif isinstance(node, exp.Between): 70 _coerce_date(node.this, node.args["low"]) 71 elif isinstance(node, exp.Extract) and not node.expression.type.is_type( 72 *exp.DataType.TEMPORAL_TYPES 73 ): 74 _replace_cast(node.expression, exp.DataType.Type.DATETIME) 75 elif isinstance(node, (exp.DateAdd, exp.DateSub, exp.DateTrunc)): 76 _coerce_timeunit_arg(node.this, node.unit) 77 elif isinstance(node, exp.DateDiff): 78 _coerce_datediff_args(node) 79 80 return node
def
remove_redundant_casts( expression: sqlglot.expressions.Expression) -> sqlglot.expressions.Expression:
def
ensure_bools( expression: sqlglot.expressions.Expression, replace_func: Callable[[sqlglot.expressions.Expression], NoneType]) -> sqlglot.expressions.Expression:
93def ensure_bools( 94 expression: exp.Expression, replace_func: t.Callable[[exp.Expression], None] 95) -> exp.Expression: 96 if isinstance(expression, exp.Connector): 97 replace_func(expression.left) 98 replace_func(expression.right) 99 elif isinstance(expression, exp.Not): 100 replace_func(expression.this) 101 # We can't replace num in CASE x WHEN num ..., because it's not the full predicate 102 elif isinstance(expression, exp.If) and not ( 103 isinstance(expression.parent, exp.Case) and expression.parent.this 104 ): 105 replace_func(expression.this) 106 elif isinstance(expression, (exp.Where, exp.Having)): 107 replace_func(expression.this) 108 109 return expression
def
remove_ascending_order( expression: sqlglot.expressions.Expression) -> sqlglot.expressions.Expression: