public static string GetSqlStart(UserId requesterId, SqlQuerySource source)
{
bool fetchAdditionalColumns = source == SqlQuerySource.PreviewNewsfeed || source == SqlQuerySource.FullPost;
var result = new StringBuilder();
if (source == SqlQuerySource.FullPost)
{
result.Append(string.Format(
"SELECT {0}, {1}, {2}, {3}, ",
Post.Fields.Content,
Post.Fields.PreviewText,
Blog.Fields.HeaderImageFileId,
Blog.Fields.Introduction));
}
else
{
result.Append(string.Format("SELECT {0},", Post.Fields.PreviewText));
}
result.Append(SqlSelectPartial);
if (requesterId != null)
{
result.Append(SqlHasLikedSelect);
if (fetchAdditionalColumns)
{
result.Append(SqlIsFreePostSelect);
}
}
if (fetchAdditionalColumns)
{
result.Append(SqlPreviewInformationSelect);
}
result.Append(SqlFromPartial);
if (requesterId != null)
{
result.Append(SqlHasLikedFromClause);
if (fetchAdditionalColumns)
{
result.Append(SqlIsFreePostFromClause);
}
}
if (fetchAdditionalColumns)
{
result.Append(SqlPreviewInformationClause);
}
return(result.ToString());
}
private void GenerateSource(SqlGenerator sql, SqlQuerySource from)
{
if (from is SqlTableSource table)
{
sql.Add($"{table.Name} {table.Alias}");
return;
}
// Select 10 as value
if (from is SqlConstantSource constant)
{
sql.NewLine();
sql.Add("SELECT ");
GenerateCommaSep(sql, constant.ValueExpressions, false, (exp, i) => {
sql.Add($"{GenerateConstant(exp)} AS {constant.Columns[i].Name}");
});
return;
}
if (from is SqlSubQuerySource sub)
{
sql.Add("(");
GenerateSource(sql, sub.Source);
sql.Add($") {sub.Alias}");
return;
}
if (from is SqlUnionSource union)
{
sql.Add("(");
sql.Indent();
foreach (var u in union.Sources)
{
GenerateSource(sql, u);
if (u != union.Sources.Last())
{
sql.NewLine();
sql.Add(union.UnionAll ? "UNION ALL" : "UNION");
}
}
sql.UnIndent();
sql.NewLine();
sql.Add($") {union.Alias}");
return;
}
throw new NotImplementedException($"Could not generate source from {from.GetType()}");
}
public SqlSubQuerySource(SqlQuerySource source, string alias) : base(source.Columns, alias)
{
Source = source;
}
public SqlColumnExpression(FieldType type, string name, SqlQuerySource source) : base(type)
{
Name = name;
Source = source;
}
