protected override Expression VisitSubSelect(SubSelectExpression subSelectExpression)
{
var parentSearchCondition = _isSearchCondition;
var subquery = (SelectExpression)Visit(subSelectExpression.Subquery);
_isSearchCondition = parentSearchCondition;
return(ApplyConversion(subSelectExpression.Update(subquery), condition: false));
}
/// <summary>
/// Main SQL builder
/// </summary>
/// <param name="selectExpression"></param>
/// <param name="queryContext"></param>
/// <returns></returns>
public SqlStatement Build(SelectExpression selectExpression, QueryContext queryContext)
{
var translator = GetTranslator(queryContext.DataContext.Vendor.SqlProvider);
var sqlProvider = queryContext.DataContext.Vendor.SqlProvider;
selectExpression = translator.OuterExpression(selectExpression);
// A scope usually has:
// - a SELECT: the operation creating a CLR object with data coming from SQL tier
// - a FROM: list of tables
// - a WHERE: list of conditions
// - a GROUP BY: grouping by selected columns
// - a ORDER BY: sort
var select = BuildSelect(selectExpression, queryContext);
if (select.ToString() == string.Empty)
{
SubSelectExpression subselect = null;
if (selectExpression.Tables.Count == 1)
{
subselect = selectExpression.Tables[0] as SubSelectExpression;
}
if (subselect != null)
{
return(sqlProvider.GetParenthesis(Build(subselect.Select, queryContext)));
}
}
// TODO: the following might be wrong (at least this might be the wrong place to do this
if (select.ToString() == string.Empty)
{
select = new SqlStatement("SELECT " + sqlProvider.GetLiteral(null) + " AS " + sqlProvider.GetSafeName("Empty"));
}
var tables = GetSortedTables(selectExpression);
var from = BuildFrom(tables, queryContext);
var join = BuildJoin(tables, queryContext);
var where = BuildWhere(tables, selectExpression.Where, queryContext);
var groupBy = BuildGroupBy(selectExpression.Group, queryContext);
var having = BuildHaving(selectExpression.Where, queryContext);
var orderBy = BuildOrderBy(selectExpression.OrderBy, queryContext);
select = Join(queryContext, select, from, join, where, groupBy, having, orderBy);
select = BuildLimit(selectExpression, select, queryContext);
if (selectExpression.NextSelectExpression != null)
{
var nextLiteralSelect = Build(selectExpression.NextSelectExpression, queryContext);
select = queryContext.DataContext.Vendor.SqlProvider.GetLiteral(
selectExpression.NextSelectExpressionOperator,
select, nextLiteralSelect);
}
return(select);
}
protected override Expression VisitSubSelect(SubSelectExpression subSelectExpression)
{
_relationalCommandBuilder.Append("(");
using (_relationalCommandBuilder.Indent())
{
Visit(subSelectExpression.Subquery);
}
_relationalCommandBuilder.Append(")");
return(subSelectExpression);
}
protected virtual SqlStatement BuildFrom(IList <TableExpression> tables, QueryContext queryContext)
{
var sqlProvider = queryContext.DataContext.Vendor.SqlProvider;
var fromClauses = new List <SqlStatement>();
foreach (var tableExpression in tables)
{
if (!MustDeclareAsJoin(tables, tableExpression))
{
if (tableExpression.Alias != null)
{
string tableAlias;
// All subqueries has an alias in FROM
SubSelectExpression subquery = tableExpression as SubSelectExpression;
if (subquery == null)
{
tableAlias = sqlProvider.GetTableAsAlias(tableExpression.Name, tableExpression.Alias);
}
else
{
var subqueryStatements = new SqlStatement(Build(subquery.Select, queryContext));
tableAlias = sqlProvider.GetSubQueryAsAlias(subqueryStatements.ToString(), tableExpression.Alias);
}
if ((tableExpression.JoinType & TableJoinType.LeftOuter) != 0)
{
tableAlias = "/* LEFT OUTER */ " + tableAlias;
}
if ((tableExpression.JoinType & TableJoinType.RightOuter) != 0)
{
tableAlias = "/* RIGHT OUTER */ " + tableAlias;
}
fromClauses.Add(tableAlias);
}
else
{
fromClauses.Add(sqlProvider.GetTable(tableExpression.Name));
}
}
}
return(sqlProvider.GetFromClause(fromClauses.ToArray()));
}
protected virtual SqlStatement BuildFrom(IList <TableExpression> tables)
{
var sqlProvider = this._dbModel.LinqSqlProvider;
var fromClauses = new List <SqlStatement>();
foreach (var tableExpression in tables)
{
if (!MustDeclareAsJoin(tables, tableExpression))
{
if (tableExpression.Alias != null)
{
string tableRef;
// All subqueries has an alias in FROM
SubSelectExpression subquery = tableExpression as SubSelectExpression;
if (subquery == null)
{
tableRef = _sqlProvider.GetTable(tableExpression);
}
else
{
var subqueryStatements = new SqlStatement(BuildSelectSql(subquery.Select));
tableRef = _sqlProvider.GetSubQueryAsAlias(subqueryStatements.ToString(), tableExpression.Alias);
}
if ((tableExpression.JoinType & TableJoinType.LeftOuter) != 0)
{
tableRef = "/* LEFT OUTER */ " + tableRef;
}
if ((tableExpression.JoinType & TableJoinType.RightOuter) != 0)
{
tableRef = "/* RIGHT OUTER */ " + tableRef;
}
fromClauses.Add(tableRef);
}
else
{
fromClauses.Add(_sqlProvider.GetTable(tableExpression));
}
}
}
return(_sqlProvider.GetFromClause(fromClauses.ToArray()));
}
protected abstract Expression VisitSubSelect(SubSelectExpression subSelectExpression);
protected override Expression VisitSubSelect(SubSelectExpression subSelectExpression)
{
var subquery = (SelectExpression)Visit(subSelectExpression.Subquery);
return(subSelectExpression.Update(subquery));
}
