Add support for SELECT_JSON statements.

internal/jet/projection.go

@@ -3,6 +3,7 @@ package jet
 // 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)
+	serializeForJsonObj(statement StatementType, out *SQLBuilder)
 	fromImpl(subQuery SelectTable) Projection
 }
 
@@ -28,6 +29,10 @@ func (pl ProjectionList) serializeForProjection(statement StatementType, out *SQ
 	SerializeProjectionList(statement, pl, out)
 }
 
+func (pl ProjectionList) serializeForJsonObj(statement StatementType, out *SQLBuilder) {
+	SerializeProjectionListJsonObj(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.*', or it can be an empty string, which will remove existing table alias.
 // For instance: If projection list has a column 'Artist.Name', and tableAlias is 'Musician.*', returned projection list will
@@ -79,3 +84,10 @@ func (pl ProjectionList) Except(toExclude ...Column) ProjectionList {
 
 	return ret
 }
+
+// JsonProjectionList redefines []Projection so projections can be serialized as json object key/values
+type JsonProjectionList []Projection
+
+func (j JsonProjectionList) serialize(statement StatementType, out *SQLBuilder, options ...SerializeOption) {
+	SerializeProjectionListJsonObj(statement, j, out)
+}