Method VisitQuerySpecification

query/sql/sql_parser.go:405–518

VisitQuerySpecification visits the node

(ctx *antlrgen.QuerySpecificationContext)

// VisitQuerySpecification visits the node
func (v *ASTBuilder) VisitQuerySpecification(ctx *antlrgen.QuerySpecificationContext) interface{} {
	v.Logger.Debugf("VisitQuerySpecification: %s", ctx.GetText())

	level, levelWith, levelQuery := v.getCtxLevels(v.SQL2AqlCtx)

	// handle from => join/table
	// first process from clause so that subquery/withQuery identifier can be found in expression
	v.SQL2AqlCtx.exprOrigin = ExprOriginJoinOn
	ctxArrRelation := ctx.AllRelation()
	arrRelations := make([]tree.IRelation, len(ctxArrRelation))
	for i, c := range ctxArrRelation {
		v.setCtxLevels(v.SQL2AqlCtx, level, levelWith, levelQuery)
		arrRelations[i], _ = v.Visit(c).(tree.IRelation)
	}

	var myFrom tree.IRelation
	if len(arrRelations) > 0 {
		relationL := arrRelations[0]
		// synthesize implicit join nodes
		for i := 1; i < len(arrRelations); i++ {
			relationR := arrRelations[i]
			relationL = tree.NewJoin(v.getLocation(ctx), tree.IMPLICIT, relationL, relationR, nil)
			relationL.SetValue(fmt.Sprintf("Join: (%s)", v.getText(ctxArrRelation[i])))
		}
		myFrom = relationL
	}

	// handle select => measure
	v.SQL2AqlCtx.exprOrigin = ExprOriginOthers
	ctxArrSelectItem := ctx.AllSelectItem()
	arrSelectItems := make([]tree.ISelectItem, len(ctxArrSelectItem))
	for i, c := range ctxArrSelectItem {
		v.setCtxLevels(v.SQL2AqlCtx, level, levelWith, levelQuery)
		arrSelectItems[i], _ = v.Visit(c).(tree.ISelectItem)

		if i < len(v.SQL2AqlCtx.MapMeasures[v.SQL2AqlCtx.mapKey]) {
			// handle subquery/withQuery with columnAliases,8
			// subquery/withQuery columnalias has higher priority, ignore subquery/withQuery selectSingle identifier
			switch item := arrSelectItems[i].(type) {
			case *tree.SingleColumn:
				v.SQL2AqlCtx.MapMeasures[v.SQL2AqlCtx.mapKey][i].Expr = util.GetSubstring(item.Expression.GetValue())
			case *tree.AllColumns:
				v.SQL2AqlCtx.MapMeasures[v.SQL2AqlCtx.mapKey][i].Expr = v.getText(c)
			}
		} else {
			// handle query or subquery/withQuery w/o columnAliases
			switch item := arrSelectItems[i].(type) {
			case *tree.SingleColumn:
				var alias string
				if item.Alias != nil {
					alias = util.GetSubstring(item.Alias.GetValue())
				}
				v.SQL2AqlCtx.MapMeasures[v.SQL2AqlCtx.mapKey] = append(v.SQL2AqlCtx.MapMeasures[v.SQL2AqlCtx.mapKey],
					queryCom.Measure{
						Alias: alias,
						Expr:  util.GetSubstring(item.Expression.GetValue()),
					})
			case *tree.AllColumns: