83 lines
2.6 KiB
Go
83 lines
2.6 KiB
Go
package jet
|
|
|
|
import "strings"
|
|
|
|
// Projection is interface for all projection types. Types that can be part of, for instance SELECT clause.
|
|
type Projection interface {
|
|
serializeForProjection(statement StatementType, out *SQLBuilder)
|
|
fromImpl(subQuery SelectTable) Projection
|
|
}
|
|
|
|
// SerializeForProjection is helper function for serializing projection outside of jet package
|
|
func SerializeForProjection(projection Projection, statementType StatementType, out *SQLBuilder) {
|
|
projection.serializeForProjection(statementType, out)
|
|
}
|
|
|
|
// ProjectionList is a redefined type, so that ProjectionList can be used as a Projection.
|
|
type ProjectionList []Projection
|
|
|
|
func (pl ProjectionList) fromImpl(subQuery SelectTable) Projection {
|
|
newProjectionList := ProjectionList{}
|
|
|
|
for _, projection := range pl {
|
|
newProjectionList = append(newProjectionList, projection.fromImpl(subQuery))
|
|
}
|
|
|
|
return newProjectionList
|
|
}
|
|
|
|
func (pl ProjectionList) serializeForProjection(statement StatementType, out *SQLBuilder) {
|
|
SerializeProjectionList(statement, pl, out)
|
|
}
|
|
|
|
// As will create new projection list where each column is wrapped with a new table alias.
|
|
// tableAlias should be in the form 'name' or 'name.*'.
|
|
// For instance: If projection list has a column 'Artist.Name', and tableAlias is 'Musician.*', returned projection list will
|
|
// have a column wrapped in alias 'Musician.Name'.
|
|
func (pl ProjectionList) As(tableAlias string) ProjectionList {
|
|
tableAlias = strings.TrimRight(tableAlias, ".*")
|
|
|
|
newProjectionList := ProjectionList{}
|
|
|
|
for _, projection := range pl {
|
|
switch p := projection.(type) {
|
|
case ProjectionList:
|
|
newProjectionList = append(newProjectionList, p.As(tableAlias))
|
|
case ColumnExpression:
|
|
newProjectionList = append(newProjectionList, newAlias(p, tableAlias+"."+p.Name()))
|
|
case *alias:
|
|
newAlias := *p
|
|
_, columnName := extractTableAndColumnName(newAlias.alias)
|
|
newAlias.alias = tableAlias + "." + columnName
|
|
newProjectionList = append(newProjectionList, &newAlias)
|
|
}
|
|
}
|
|
|
|
return newProjectionList
|
|
}
|
|
|
|
// Except will create new projection list in which columns contained in excluded column names are removed
|
|
func (pl ProjectionList) Except(toExclude ...Column) ProjectionList {
|
|
excludedColumnList := UnwidColumnList(toExclude)
|
|
excludedColumnNames := map[string]bool{}
|
|
|
|
for _, excludedColumn := range excludedColumnList {
|
|
excludedColumnNames[excludedColumn.Name()] = true
|
|
}
|
|
|
|
var ret ProjectionList
|
|
|
|
for _, projection := range pl {
|
|
switch p := projection.(type) {
|
|
case ProjectionList:
|
|
ret = append(ret, p.Except(toExclude...))
|
|
case ColumnExpression:
|
|
if excludedColumnNames[p.Name()] {
|
|
continue
|
|
}
|
|
ret = append(ret, p)
|
|
}
|
|
}
|
|
|
|
return ret
|
|
}
|