protected void ParseReturining(ExpressionParser parser)
{
var collection = parser.Collection;
var lex = collection.CurrentLexem();
if (lex == null)
{
return;
}
if (lex.LexemText.ToLower() == "returning")
{
collection.GotoNextMust();
int idx = collection.IndexLexem;
ColumnClauseParser colsParser = new ColumnClauseParser();
colsParser.Parse(collection);
if (colsParser.Columns.Count == 0)
{
collection.Error("Columnn not found", collection.Get(idx));
}
ReturningColumns.Replace(colsParser.Columns);
}
}
public override void Parse()
{
//текщая лексема SELECT
var le = Collection.GotoNext();
if (le == null) Collection.Error("неожиданный конец", Collection.GetPrev());
if (le.LexemText.ToLower() == "distinct")
{
SelectExpresion.Distinct = true;
le = Collection.GotoNextMust();
}
else if (le.LexemText.ToLower() == "all")
{
le = Collection.GotoNextMust();
}
var idx = Collection.IndexLexem;
ColumnClauseParser colsParser = new ColumnClauseParser();
colsParser.Parse(Collection);
if (colsParser.Columns.Count == 0) Collection.Error("Columnn not found", Collection.Get(idx));
Results.Add(SelectExpresion);
SelectExpresion.Columns.Replace(colsParser.Columns);
var lex = Collection.CurrentLexem();
if (lex == null) return;
if (lex.LexemText.ToLower() != "from") return;
lex = Collection.GotoNext();
FromParser fc = new FromParser();
fc.Parse(Collection);
SelectExpresion.Tables.Replace(fc.Tables);
lex = Collection.CurrentLexem();
if (lex == null) return;
if (lex.LexemText.ToLower() == "where")
{
lex = Collection.GotoNext();
if (lex == null) Collection.Error("Where clause not found", Collection.GetPrev());
idx = Collection.IndexLexem;
ExpressionParser tonode = new ExpressionParser(Collection);
tonode.Parse();
if (tonode.Results.Count != 1) Collection.Error("не верное число параметров", Collection.Get(idx));
SelectExpresion.WhereExpr = tonode.Single();
}
lex = Collection.CurrentLexem();
if (lex == null) return;
if (lex.LexemText.ToLower() == "having")
{
lex = Collection.GotoNext();
if (lex == null) Collection.Error("Having clause not found", Collection.GetPrev());
idx = Collection.IndexLexem;
ExpressionParser tonode = new ExpressionParser(Collection);
tonode.Parse();
if (tonode.Results.Count != 1) Collection.Error("не верное число параметров", Collection.Get(idx));
SelectExpresion.Having = tonode.Single();
}
lex = Collection.CurrentLexem();
if (lex == null) return;
if (lex.LexemText.ToLower() == "group")
{
lex = Collection.GotoNext();
if (lex == null) Collection.Error("Group by clause error", Collection.GetPrev());
if (lex.LexemText.ToLower() != "by") Collection.Error("Group by clause error", Collection.GetPrev());
lex = Collection.GotoNext();
OrderByParser gb = new OrderByParser();
gb.Parse(Collection, false);
SelectExpresion.GroupBys.Replace(gb.Columns);
if (SelectExpresion.GroupBys.Count == 0) Collection.Error("\"Group by\" columns not found", Collection.Get(idx));
lex = Collection.CurrentLexem();
}
lex = Collection.CurrentLexem();
if (lex == null) return;
if (lex.LexemText.ToLower() == "order")
{
lex = Collection.GotoNext();
if (lex == null) Collection.Error("Order by clause error", Collection.GetPrev());
if (lex.LexemText.ToLower() != "by") Collection.ErrorWaitKeyWord("BY", Collection.GetPrev());
lex = Collection.GotoNext();
OrderByParser gb = new OrderByParser();
gb.Parse(Collection, true);
SelectExpresion.OrderBys.Replace(gb.Columns.Select(a => (OrderByClause)a).ToList());
if (SelectExpresion.OrderBys.Count == 0) Collection.Error("\"Order by\" columns not found", Collection.Get(idx));
lex = Collection.CurrentLexem();
}
lex = Collection.CurrentLexem();
if (lex == null) return;
if (lex.LexemText.ToLower() == "limit")
{
lex = Collection.GotoNext();
if (lex == null) Collection.Error("Limit clause not found", Collection.GetPrev());
ExpressionParser tonode = new ExpressionParser(Collection);
tonode.Parse();
SelectExpresion.LimitRecords = tonode.Single().GetIntResultOut(null);
}
lex = Collection.CurrentLexem();
if (lex == null) return;
if (lex.LexemText.ToLower() == "offset")
{
lex = Collection.GotoNext();
if (lex == null) Collection.Error("Offset clause not found", Collection.GetPrev());
ExpressionParser tonode = new ExpressionParser(Collection);
tonode.Parse();
SelectExpresion.SkipRecords = tonode.Single().GetIntResultOut(null);
}
while (true)
{
lex = Collection.CurrentLexem();
if (lex == null) return;
string s = lex.LexemText.ToLower();
if (s == "union" || s == "intersect" || s == "except")
{
lex = Collection.GotoNextMust();
ExtSelectClause extS = new ExtSelectClause();
extS.Select = new SelectExpresion();
if (s == "union" && lex.LexemText.ToLower() == "all")
{
extS.Operation = SelectOperation.UnionAll;
lex = Collection.GotoNextMust();
}
else if (s == "union") extS.Operation = SelectOperation.Union;
if (s == "intersect") extS.Operation = SelectOperation.Intersect;
if (s == "except") extS.Operation = SelectOperation.Except;
if (lex.LexemText.ToLower() != "select") Collection.Error("\"SELECT\" clouse is not found", lex);
SelectParser sp = new SelectParser(Collection);
sp.SelectExpresion = extS.Select;
sp.Parse();
SelectExpresion.ExtSelects.Add(extS);
}
else break;
}
}
