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| 1 | +// Copyright 2026 Dolthub, Inc. |
| 2 | +// |
| 3 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | +// you may not use this file except in compliance with the License. |
| 5 | +// You may obtain a copy of the License at |
| 6 | +// |
| 7 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | +// |
| 9 | +// Unless required by applicable law or agreed to in writing, software |
| 10 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | +// See the License for the specific language governing permissions and |
| 13 | +// limitations under the License. |
| 14 | + |
| 15 | +package expression |
| 16 | + |
| 17 | +import ( |
| 18 | + "github.com/cockroachdb/errors" |
| 19 | + "github.com/dolthub/go-mysql-server/sql" |
| 20 | + "github.com/dolthub/go-mysql-server/sql/expression" |
| 21 | + vitess "github.com/dolthub/vitess/go/vt/sqlparser" |
| 22 | + |
| 23 | + "github.com/dolthub/doltgresql/server/functions/framework" |
| 24 | + |
| 25 | + pgtypes "github.com/dolthub/doltgresql/server/types" |
| 26 | +) |
| 27 | + |
| 28 | +// IsDistinctFrom represents IS DISTINCT FROM expression. |
| 29 | +type IsDistinctFrom struct { |
| 30 | + leftExpr sql.Expression |
| 31 | + rightExpr sql.Expression |
| 32 | + staticLeftLiteral *expression.Literal |
| 33 | + staticRightLiteral *expression.Literal |
| 34 | + notEqualFunc *framework.CompiledFunction |
| 35 | +} |
| 36 | + |
| 37 | +var _ vitess.Injectable = (*IsDistinctFrom)(nil) |
| 38 | +var _ sql.Expression = (*IsDistinctFrom)(nil) |
| 39 | + |
| 40 | +// NewIsDistinctFrom returns a new *IsDistinctFrom. |
| 41 | +func NewIsDistinctFrom() *IsDistinctFrom { |
| 42 | + return &IsDistinctFrom{ |
| 43 | + leftExpr: nil, |
| 44 | + rightExpr: nil, |
| 45 | + } |
| 46 | +} |
| 47 | + |
| 48 | +// Children implements the sql.Expression interface. |
| 49 | +func (n *IsDistinctFrom) Children() []sql.Expression { |
| 50 | + return []sql.Expression{n.leftExpr, n.rightExpr} |
| 51 | +} |
| 52 | + |
| 53 | +// Eval implements the sql.Expression interface. |
| 54 | +func (n *IsDistinctFrom) Eval(ctx *sql.Context, row sql.Row) (any, error) { |
| 55 | + left, err := n.leftExpr.Eval(ctx, row) |
| 56 | + if err != nil { |
| 57 | + return nil, err |
| 58 | + } |
| 59 | + right, err := n.rightExpr.Eval(ctx, row) |
| 60 | + if err != nil { |
| 61 | + return nil, err |
| 62 | + } |
| 63 | + |
| 64 | + if left == nil && right == nil { |
| 65 | + return false, nil |
| 66 | + } else if left == nil || right == nil { |
| 67 | + return true, nil |
| 68 | + } |
| 69 | + |
| 70 | + n.staticLeftLiteral.Val = left |
| 71 | + n.staticRightLiteral.Val = right |
| 72 | + |
| 73 | + if n.notEqualFunc == nil { |
| 74 | + return nil, errors.Errorf("input types do not match: %s %s", n.leftExpr.Type().String(), n.rightExpr.Type().String()) |
| 75 | + } |
| 76 | + return n.notEqualFunc.Eval(ctx, row) |
| 77 | +} |
| 78 | + |
| 79 | +// IsNullable implements the sql.Expression interface. |
| 80 | +func (n *IsDistinctFrom) IsNullable() bool { |
| 81 | + return true |
| 82 | +} |
| 83 | + |
| 84 | +// Resolved implements the sql.Expression interface. |
| 85 | +func (n *IsDistinctFrom) Resolved() bool { |
| 86 | + if n.leftExpr == nil || n.rightExpr == nil { |
| 87 | + return false |
| 88 | + } |
| 89 | + return n.leftExpr.Resolved() && n.rightExpr.Resolved() |
| 90 | +} |
| 91 | + |
| 92 | +// String implements the sql.Expression interface. |
| 93 | +func (n *IsDistinctFrom) String() string { |
| 94 | + return n.leftExpr.String() + " IS DISTINCT FROM " + n.rightExpr.String() |
| 95 | +} |
| 96 | + |
| 97 | +// Type implements the sql.Expression interface. |
| 98 | +func (n *IsDistinctFrom) Type() sql.Type { |
| 99 | + return pgtypes.Bool |
| 100 | +} |
| 101 | + |
| 102 | +// WithChildren implements the sql.Expression interface. |
| 103 | +func (n *IsDistinctFrom) WithChildren(children ...sql.Expression) (sql.Expression, error) { |
| 104 | + if len(children) != 2 { |
| 105 | + return nil, sql.ErrInvalidChildrenNumber.New(n, len(children), 2) |
| 106 | + } |
| 107 | + |
| 108 | + // This allows evaluating the arguments separate from function.Eval() in order to resolve NULL values. |
| 109 | + // This follows the same logic as InTuple expression. |
| 110 | + allValidChildren := true |
| 111 | + leftType, ok := children[0].Type().(*pgtypes.DoltgresType) |
| 112 | + if !ok { |
| 113 | + allValidChildren = false |
| 114 | + } |
| 115 | + rightType, ok := children[1].Type().(*pgtypes.DoltgresType) |
| 116 | + if !ok { |
| 117 | + allValidChildren = false |
| 118 | + } |
| 119 | + staticLeftLiteral := expression.NewLiteral(nil, leftType) |
| 120 | + staticRightLiteral := expression.NewLiteral(nil, rightType) |
| 121 | + |
| 122 | + if allValidChildren { |
| 123 | + cf := framework.GetBinaryFunction(framework.Operator_BinaryNotEqual).Compile("internal_binary_operator_func_<>", staticLeftLiteral, staticRightLiteral) |
| 124 | + return &IsDistinctFrom{ |
| 125 | + leftExpr: children[0], |
| 126 | + rightExpr: children[1], |
| 127 | + staticLeftLiteral: staticLeftLiteral, |
| 128 | + staticRightLiteral: staticRightLiteral, |
| 129 | + notEqualFunc: cf, |
| 130 | + }, nil |
| 131 | + } |
| 132 | + |
| 133 | + return &IsDistinctFrom{ |
| 134 | + leftExpr: children[0], |
| 135 | + rightExpr: children[1], |
| 136 | + }, nil |
| 137 | +} |
| 138 | + |
| 139 | +// WithResolvedChildren implements the vitess.InjectableExpression interface. |
| 140 | +func (n *IsDistinctFrom) WithResolvedChildren(children []any) (any, error) { |
| 141 | + if len(children) != 2 { |
| 142 | + return nil, errors.Errorf("invalid vitess child count, expected `2` but got `%d`", len(children)) |
| 143 | + } |
| 144 | + left, ok := children[0].(sql.Expression) |
| 145 | + if !ok { |
| 146 | + return nil, errors.Errorf("expected vitess child to be an expression but has type `%T`", children[0]) |
| 147 | + } |
| 148 | + right, ok := children[1].(sql.Expression) |
| 149 | + if !ok { |
| 150 | + return nil, errors.Errorf("expected vitess child to be an expression but has type `%T`", children[1]) |
| 151 | + } |
| 152 | + |
| 153 | + return n.WithChildren(left, right) |
| 154 | +} |
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