/
lower.go
59 lines (47 loc) · 1.49 KB
/
lower.go
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package function
import (
"context"
"strings"
)
import (
"github.com/pkg/errors"
)
import (
"github.com/arana-db/arana/pkg/proto"
)
// FuncLower is https://dev.mysql.com/doc/refman/5.6/en/string-functions.html#function_lower
const FuncLower = "LOWER"
var _ proto.Func = (*lowerFunc)(nil)
func init() {
proto.RegisterFunc(FuncLower, lowerFunc{})
}
type lowerFunc struct{}
func (c lowerFunc) Apply(ctx context.Context, inputs ...proto.Valuer) (proto.Value, error) {
val, err := inputs[0].Value(ctx)
if err != nil {
return nil, errors.WithStack(err)
}
if val == nil {
return nil, nil
}
return proto.NewValueString(strings.ToLower(val.String())), nil
}
func (c lowerFunc) NumInput() int {
return 1
}