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sql.go
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sql.go
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// Copyright 2015-2017, Cyrill @ Schumacher.fm and the CoreStore contributors
//
// Licensed 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 eav
import "github.com/corestoreio/pkg/util/bufferpool"
// DefaultScopeNames specifies the name of the scopes used in all EAV* function
// to generate scope based hierarchical fall backs.
var DefaultScopeNames = [...]string{"Store", "Group", "Website", "Default"}
// IfNull creates a nested IFNULL SQL statement when a scope based fall back
// hierarchy is required. Alias argument will be used as a prefix for the alias
// table name and as the final alias name.
func IfNull(alias, columnName, defaultVal string, scopeNames ...string) string {
buf := bufferpool.Get()
defer bufferpool.Put(buf)
if len(scopeNames) == 0 {
scopeNames = DefaultScopeNames[:]
}
brackets := 0
for _, n := range scopeNames {
buf.WriteString("IFNULL(")
buf.WriteRune('`')
buf.WriteString(alias)
buf.WriteString(n)
buf.WriteRune('`')
buf.WriteRune('.')
buf.WriteRune('`')
buf.WriteString(columnName)
buf.WriteRune('`')
if brackets < len(scopeNames)-1 {
buf.WriteRune(',')
}
brackets++
}
if defaultVal == "" {
defaultVal = `''`
}
buf.WriteRune(',')
buf.WriteString(defaultVal)
for i := 0; i < brackets; i++ {
buf.WriteRune(')')
}
buf.WriteString(" AS ")
buf.WriteRune('`')
buf.WriteString(alias)
buf.WriteRune('`')
return buf.String()
}