public static FromClause Build(PlSqlParser.FromClauseContext context)
{
if (context == null)
return null;
var clause = new FromClause();
var list = context.tableRefList();
if (list.IsEmpty)
throw new ParseCanceledException("No source set in FROM clause");
var tableRefs = list.tableRef().Select(FormTableRef);
bool joinSeen = false;
bool first = true;
foreach (var tableRef in tableRefs) {
if (joinSeen)
throw new ParseCanceledException("Invalid join clause");
var source = tableRef.Source;
if (source.SubQuery != null) {
clause.AddSubQuery(source.Alias, source.SubQuery);
} else if (source.TableName != null) {
clause.AddTable(source.Alias, source.TableName);
}
foreach (var joinNode in tableRef.Join) {
var joinSource = joinNode.Source;
if (joinSource.SubQuery != null) {
clause.AddSubQuery(joinSource.Alias, joinSource.SubQuery);
} else if (joinSource.TableName != null) {
clause.AddTable(joinSource.Alias, joinSource.TableName);
}
clause.Join(joinNode.JoinType, joinNode.OnExpression);
joinSeen = true;
}
if (!first && !joinSeen) {
clause.Join(JoinType.Inner, null);
}
first = false;
}
return clause;
}