private void CorrectSkip(SelectQuery selectQuery)
{
((ISqlExpressionWalkable)selectQuery).Walk(new WalkOptions(), e =>
{
if (e is SelectQuery q && q.Select.SkipValue != null && SqlProviderFlags.GetIsSkipSupportedFlag(q) && q.OrderBy.IsEmpty)
{
if (q.Select.Columns.Count == 0)
{
var source = q.Select.From.Tables[0].Source;
var keys = source.GetKeys(true);
foreach (var key in keys)
{
q.Select.AddNew(key);
}
}
for (var i = 0; i < q.Select.Columns.Count; i++)
{
q.OrderBy.ExprAsc(new SqlValue(i + 1));
}
if (q.OrderBy.IsEmpty)
{
throw new LinqToDBException("Order by required for Skip operation.");
}
}
return(e);
}
protected void CorrectRootSkip(SelectQuery selectQuery)
{
if (selectQuery != null && selectQuery.Select.SkipValue != null && SqlProviderFlags.GetIsSkipSupportedFlag(selectQuery) && selectQuery.OrderBy.IsEmpty)
{
if (selectQuery.Select.Columns.Count == 0)
{
var source = selectQuery.Select.From.Tables[0].Source;
var keys = source.GetKeys(true);
foreach (var key in keys)
{
selectQuery.Select.AddNew(key);
}
}
for (var i = 0; i < selectQuery.Select.Columns.Count; i++)
{
selectQuery.OrderBy.ExprAsc(new SqlValue(i + 1));
}
if (selectQuery.OrderBy.IsEmpty)
{
throw new LinqToDBException("Order by required for Skip operation.");
}
}
}
public override SqlStatement TransformStatement(SqlStatement statement)
{
statement = SeparateDistinctFromPagination(statement, q => q.Select.SkipValue != null);
statement = ReplaceDistinctOrderByWithRowNumber(statement, q => q.Select.SkipValue != null);
statement = ReplaceTakeSkipWithRowNumber(statement, query => query.Select.SkipValue != null && SqlProviderFlags.GetIsSkipSupportedFlag(query.Select.TakeValue, query.Select.SkipValue), true);
return(statement.QueryType switch {
QueryType.Delete => GetAlternativeDelete((SqlDeleteStatement)statement),
QueryType.Update => GetAlternativeUpdate((SqlUpdateStatement)statement),
_ => statement,
});
public override SqlStatement TransformStatement(SqlStatement statement)
{
// DB2 LUW 9/10 supports only FETCH, v11 adds OFFSET, but for that we need to introduce versions into DB2 provider first
statement = SeparateDistinctFromPagination(statement, q => q.Select.SkipValue != null);
statement = ReplaceDistinctOrderByWithRowNumber(statement, q => q.Select.SkipValue != null);
statement = ReplaceTakeSkipWithRowNumber(statement, query => query.Select.SkipValue != null && SqlProviderFlags.GetIsSkipSupportedFlag(query), true);
return(statement.QueryType switch
{
QueryType.Delete => GetAlternativeDelete((SqlDeleteStatement)statement),
QueryType.Update => GetAlternativeUpdate((SqlUpdateStatement)statement),
_ => statement,
});