github.com/dolthub/go-mysql-server@v0.18.0/sql/rowexec/existssubquery_test.go (about)

     1  // Copyright 2020-2021 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 rowexec
    16  
    17  import (
    18  	"testing"
    19  
    20  	"github.com/stretchr/testify/require"
    21  
    22  	"github.com/dolthub/go-mysql-server/memory"
    23  	"github.com/dolthub/go-mysql-server/sql"
    24  	"github.com/dolthub/go-mysql-server/sql/expression"
    25  	"github.com/dolthub/go-mysql-server/sql/plan"
    26  	"github.com/dolthub/go-mysql-server/sql/types"
    27  )
    28  
    29  func TestExistsSubquery(t *testing.T) {
    30  	db := memory.NewDatabase("test")
    31  	pro := memory.NewDBProvider(db)
    32  	ctx := newContext(pro)
    33  
    34  	table := memory.NewTable(db.BaseDatabase, "foo", sql.NewPrimaryKeySchema(sql.Schema{
    35  		{Name: "t", Source: "foo", Type: types.Text},
    36  	}), nil)
    37  
    38  	require.NoError(t, table.Insert(ctx, sql.Row{"one"}))
    39  	require.NoError(t, table.Insert(ctx, sql.Row{"two"}))
    40  	require.NoError(t, table.Insert(ctx, sql.Row{"three"}))
    41  
    42  	emptyTable := memory.NewTable(db.BaseDatabase, "empty", sql.NewPrimaryKeySchema(sql.Schema{
    43  		{Name: "t", Source: "empty", Type: types.Int64},
    44  	}), nil)
    45  
    46  	project := func(expr sql.Expression, tbl *memory.Table) sql.Node {
    47  		return plan.NewProject([]sql.Expression{
    48  			expr,
    49  		}, plan.NewResolvedTable(tbl, nil, nil))
    50  	}
    51  
    52  	testCases := []struct {
    53  		name     string
    54  		subquery sql.Node
    55  		row      sql.Row
    56  		result   interface{}
    57  	}{
    58  		{
    59  			"Null returns as true",
    60  			project(
    61  				expression.NewGetField(1, types.Text, "foo", false), table,
    62  			),
    63  			sql.NewRow(nil),
    64  			true,
    65  		},
    66  		{
    67  			"Non NULL evaluates as true",
    68  			project(
    69  				expression.NewGetField(1, types.Text, "foo", false), table,
    70  			),
    71  			sql.NewRow("four"),
    72  			true,
    73  		},
    74  		{
    75  			"Empty Set Passes",
    76  			project(
    77  				expression.NewGetField(1, types.Text, "foo", false), emptyTable,
    78  			),
    79  			sql.NewRow(),
    80  			false,
    81  		},
    82  	}
    83  
    84  	for _, tt := range testCases {
    85  		t.Run(tt.name, func(t *testing.T) {
    86  			require := require.New(t)
    87  
    88  			result, err := plan.NewExistsSubquery(
    89  				plan.NewSubquery(tt.subquery, "").WithExecBuilder(DefaultBuilder),
    90  			).Eval(ctx, tt.row)
    91  			require.NoError(err)
    92  			require.Equal(tt.result, result)
    93  
    94  			// Test Not Exists
    95  			result, err = expression.NewNot(plan.NewExistsSubquery(
    96  				plan.NewSubquery(tt.subquery, "").WithExecBuilder(DefaultBuilder),
    97  			)).Eval(ctx, tt.row)
    98  
    99  			require.NoError(err)
   100  			require.Equal(tt.result, !result.(bool))
   101  		})
   102  	}
   103  }