protected internal override Expression VisitJoin(JoinExpression join)
{
if (join.Condition != null)
{
GetColumnCollector(join.KnownAliases).Visit(join.Condition);
}
else if (join.JoinType == JoinType.CrossApply || join.JoinType == JoinType.OuterApply)
{
GetColumnCollector(join.Left.KnownAliases).Visit(join.Right);
}
SourceExpression left = this.VisitSource(join.Left);
SourceExpression right = this.VisitSource(join.Right);
Expression? condition = this.Visit(join.Condition);
if (left != join.Left || right != join.Right || condition != join.Condition)
{
return(new JoinExpression(join.JoinType, left, right, condition));
}
return(join);
}
private static IEnumerable <ColumnExpression> KeysJoin(JoinExpression join)
{
switch (join.JoinType)
{
case JoinType.SingleRowLeftOuterJoin:
return(Keys(join.Left));
case JoinType.CrossJoin:
case JoinType.InnerJoin:
case JoinType.CrossApply:
case JoinType.OuterApply:
case JoinType.LeftOuterJoin:
case JoinType.RightOuterJoin:
case JoinType.FullOuterJoin:
return(Keys(join.Left).Concat(Keys(join.Right)));
default:
break;
}
throw new InvalidOperationException("Unexpected Join Type");
}
protected internal override Expression VisitJoin(JoinExpression join)
{
if (join.JoinType == JoinType.SingleRowLeftOuterJoin)
{
var source = join.Right as SourceWithAliasExpression;
var hs = allColumnsUsed.TryGetC(source.Alias);
if (hs == null || hs.Count == 0)
{
return(Visit(join.Left));
}
}
if (join.JoinType == JoinType.OuterApply || join.JoinType == JoinType.LeftOuterJoin)
{
var sql = join.Right as SelectExpression;
if (sql != null && sql.IsOneRow())
{
var hs = allColumnsUsed.TryGetC(sql.Alias);
if (hs == null || hs.Count == 0)
{
return(Visit(join.Left));
}
}
}
// visit join in reverse order
Expression condition = this.Visit(join.Condition);
SourceExpression right = this.VisitSource(join.Right);
SourceExpression left = this.VisitSource(join.Left);
if (left != join.Left || right != join.Right || condition != join.Condition)
{
return(new JoinExpression(join.JoinType, left, right, condition));
}
return(join);
}
protected internal override Expression VisitJoin(JoinExpression join)
{
SourceExpression left = this.VisitSource(join.Left);
SourceExpression right = this.VisitSource(join.Right);
Expression? condition = this.Visit(join.Condition);
if (join.JoinType == JoinType.CrossApply || join.JoinType == JoinType.OuterApply)
{
if (right is TableExpression)
{
return(new JoinExpression(join.JoinType == JoinType.OuterApply ? JoinType.LeftOuterJoin : JoinType.InnerJoin, left, right,
Schema.Current.Settings.IsPostgres ? (Expression) new SqlConstantExpression(true) :
Expression.Equal(new SqlConstantExpression(1), new SqlConstantExpression(1))));
}
}
if (left != join.Left || right != join.Right || condition != join.Condition)
{
return(new JoinExpression(join.JoinType, left, right, condition));
}
return(join);
}
