gorm/clause/joins.go

80 lines
1.5 KiB
Go

package clause
import "gorm.io/gorm/utils"
type JoinType string
const (
CrossJoin JoinType = "CROSS"
InnerJoin JoinType = "INNER"
LeftJoin JoinType = "LEFT"
RightJoin JoinType = "RIGHT"
)
type JoinTarget struct {
Type JoinType
Association string
Subquery Expression
Table string
}
func Has(name string) JoinTarget {
return JoinTarget{Type: LeftJoin, Association: name}
}
func (jt JoinType) Association(name string) JoinTarget {
return JoinTarget{Type: jt, Association: name}
}
func (jt JoinType) Subquery(subquery Expression) JoinTarget {
return JoinTarget{Type: jt, Subquery: subquery}
}
func (jt JoinTarget) As(name string) JoinTarget {
jt.Table = name
return jt
}
// Join clause for from
type Join struct {
Type JoinType
Table Table
ON Where
Using []string
Expression Expression
}
func JoinTable(names ...string) Table {
return Table{
Name: utils.JoinNestedRelationNames(names),
}
}
func (join Join) Build(builder Builder) {
if join.Expression != nil {
join.Expression.Build(builder)
} else {
if join.Type != "" {
builder.WriteString(string(join.Type))
builder.WriteByte(' ')
}
builder.WriteString("JOIN ")
builder.WriteQuoted(join.Table)
if len(join.ON.Exprs) > 0 {
builder.WriteString(" ON ")
join.ON.Build(builder)
} else if len(join.Using) > 0 {
builder.WriteString(" USING (")
for idx, c := range join.Using {
if idx > 0 {
builder.WriteByte(',')
}
builder.WriteQuoted(c)
}
builder.WriteByte(')')
}
}
}