jet/mysql/set_statement.go
2020-06-27 18:48:19 +02:00

98 lines
2.7 KiB
Go

package mysql
import "github.com/go-jet/jet/v2/internal/jet"
// UNION effectively appends the result of sub-queries(select statements) into single query.
// It eliminates duplicate rows from its result.
func UNION(lhs, rhs jet.SerializerStatement, selects ...jet.SerializerStatement) setStatement {
return newSetStatementImpl(union, false, toSelectList(lhs, rhs, selects...))
}
// UNION_ALL effectively appends the result of sub-queries(select statements) into single query.
// It does not eliminates duplicate rows from its result.
func UNION_ALL(lhs, rhs jet.SerializerStatement, selects ...jet.SerializerStatement) setStatement {
return newSetStatementImpl(union, true, toSelectList(lhs, rhs, selects...))
}
type setStatement interface {
setOperators
ORDER_BY(orderByClauses ...jet.OrderByClause) setStatement
LIMIT(limit int64) setStatement
OFFSET(offset int64) setStatement
AsTable(alias string) SelectTable
}
type setOperators interface {
jet.Statement
jet.HasProjections
jet.Expression
UNION(rhs SelectStatement) setStatement
UNION_ALL(rhs SelectStatement) setStatement
}
type setOperatorsImpl struct {
parent setOperators
}
func (s *setOperatorsImpl) UNION(rhs SelectStatement) setStatement {
return UNION(s.parent, rhs)
}
func (s *setOperatorsImpl) UNION_ALL(rhs SelectStatement) setStatement {
return UNION_ALL(s.parent, rhs)
}
type setStatementImpl struct {
jet.ExpressionStatement
setOperatorsImpl
setOperator jet.ClauseSetStmtOperator
}
func newSetStatementImpl(operator string, all bool, selects []jet.SerializerStatement) setStatement {
newSetStatement := &setStatementImpl{}
newSetStatement.ExpressionStatement = jet.NewExpressionStatementImpl(Dialect, jet.SetStatementType, newSetStatement,
&newSetStatement.setOperator)
newSetStatement.setOperator.Operator = operator
newSetStatement.setOperator.All = all
newSetStatement.setOperator.Selects = selects
newSetStatement.setOperator.Limit.Count = -1
newSetStatement.setOperator.Offset.Count = -1
newSetStatement.setOperatorsImpl.parent = newSetStatement
return newSetStatement
}
func (s *setStatementImpl) ORDER_BY(orderByClauses ...jet.OrderByClause) setStatement {
s.setOperator.OrderBy.List = orderByClauses
return s
}
func (s *setStatementImpl) LIMIT(limit int64) setStatement {
s.setOperator.Limit.Count = limit
return s
}
func (s *setStatementImpl) OFFSET(offset int64) setStatement {
s.setOperator.Offset.Count = offset
return s
}
func (s *setStatementImpl) AsTable(alias string) SelectTable {
return newSelectTable(s, alias)
}
const (
union = "UNION"
)
func toSelectList(lhs, rhs jet.SerializerStatement, selects ...jet.SerializerStatement) []jet.SerializerStatement {
return append([]jet.SerializerStatement{lhs, rhs}, selects...)
}