Select.cpp 6.0 KB

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  1. /*
  2. * Copyright (c) 2021, Jan de Visser <jan@de-visser.net>
  3. *
  4. * SPDX-License-Identifier: BSD-2-Clause
  5. */
  6. #include <AK/NumericLimits.h>
  7. #include <LibSQL/AST/AST.h>
  8. #include <LibSQL/Database.h>
  9. #include <LibSQL/Meta.h>
  10. #include <LibSQL/ResultSet.h>
  11. #include <LibSQL/Row.h>
  12. namespace SQL::AST {
  13. RefPtr<SQLResult> Select::execute(ExecutionContext& context) const
  14. {
  15. NonnullRefPtrVector<ResultColumn> columns;
  16. for (auto& table_descriptor : table_or_subquery_list()) {
  17. if (!table_descriptor.is_table())
  18. return SQLResult::construct(SQLCommand::Select, SQLErrorCode::NotYetImplemented, "Sub-selects are not yet implemented");
  19. auto table_def_or_error = context.database->get_table(table_descriptor.schema_name(), table_descriptor.table_name());
  20. if (table_def_or_error.is_error())
  21. return SQLResult::construct(SQLCommand::Select, SQLErrorCode::InternalError, table_def_or_error.error());
  22. auto table = table_def_or_error.value();
  23. if (!table) {
  24. return SQLResult::construct(SQLCommand::Select, SQLErrorCode::TableDoesNotExist, table_descriptor.table_name());
  25. }
  26. if (result_column_list().size() == 1 && result_column_list()[0].type() == ResultType::All) {
  27. for (auto& col : table->columns()) {
  28. columns.append(
  29. create_ast_node<ResultColumn>(
  30. create_ast_node<ColumnNameExpression>(table->parent()->name(), table->name(), col.name()),
  31. ""));
  32. }
  33. }
  34. }
  35. VERIFY(!result_column_list().is_empty());
  36. if (result_column_list().size() != 1 || result_column_list()[0].type() != ResultType::All) {
  37. for (auto& col : result_column_list()) {
  38. if (col.type() == ResultType::All)
  39. // FIXME can have '*' for example in conjunction with computed columns
  40. return SQLResult::construct(SQL::SQLCommand::Select, SQLErrorCode::SyntaxError, "*");
  41. columns.append(col);
  42. }
  43. }
  44. context.result = SQLResult::construct();
  45. AK::NonnullRefPtr<TupleDescriptor> descriptor = AK::adopt_ref(*new TupleDescriptor);
  46. Tuple tuple(descriptor);
  47. Vector<Tuple> rows;
  48. descriptor->empend("__unity__");
  49. tuple.append(Value(SQLType::Boolean, true));
  50. rows.append(tuple);
  51. for (auto& table_descriptor : table_or_subquery_list()) {
  52. if (!table_descriptor.is_table())
  53. return SQLResult::construct(SQLCommand::Select, SQLErrorCode::NotYetImplemented, "Sub-selects are not yet implemented");
  54. auto table_def_or_error = context.database->get_table(table_descriptor.schema_name(), table_descriptor.table_name());
  55. if (table_def_or_error.is_error())
  56. return SQLResult::construct(SQLCommand::Select, SQLErrorCode::InternalError, table_def_or_error.error());
  57. auto table = table_def_or_error.value();
  58. if (table->num_columns() == 0)
  59. continue;
  60. auto old_descriptor_size = descriptor->size();
  61. descriptor->extend(table->to_tuple_descriptor());
  62. for (auto cartesian_row = rows.first(); cartesian_row.size() == old_descriptor_size; cartesian_row = rows.first()) {
  63. rows.remove(0);
  64. auto table_rows_or_error = context.database->select_all(*table);
  65. if (table_rows_or_error.is_error())
  66. return SQLResult::construct(SQLCommand::Select, SQLErrorCode::InternalError, table_rows_or_error.error());
  67. for (auto& table_row : table_rows_or_error.value()) {
  68. auto new_row = cartesian_row;
  69. new_row.extend(table_row);
  70. rows.append(new_row);
  71. }
  72. }
  73. }
  74. bool has_ordering { false };
  75. AK::NonnullRefPtr<TupleDescriptor> sort_descriptor = AK::adopt_ref(*new TupleDescriptor);
  76. for (auto& term : m_ordering_term_list) {
  77. sort_descriptor->append(TupleElementDescriptor { .order = term.order() });
  78. has_ordering = true;
  79. }
  80. Tuple sort_key(sort_descriptor);
  81. for (auto& row : rows) {
  82. context.current_row = &row;
  83. if (where_clause()) {
  84. auto where_result = where_clause()->evaluate(context);
  85. if (context.result->has_error())
  86. return context.result;
  87. if (!where_result)
  88. continue;
  89. }
  90. tuple.clear();
  91. for (auto& col : columns) {
  92. auto value = col.expression()->evaluate(context);
  93. if (context.result->has_error())
  94. return context.result;
  95. tuple.append(value);
  96. }
  97. if (has_ordering) {
  98. sort_key.clear();
  99. for (auto& term : m_ordering_term_list) {
  100. auto value = term.expression()->evaluate(context);
  101. if (context.result->has_error())
  102. return context.result;
  103. sort_key.append(value);
  104. }
  105. }
  106. context.result->insert(tuple, sort_key);
  107. }
  108. if (m_limit_clause != nullptr) {
  109. size_t limit_value = NumericLimits<size_t>::max();
  110. auto limit = m_limit_clause->limit_expression()->evaluate(context);
  111. if (!limit.is_null()) {
  112. auto limit_value_maybe = limit.to_u32();
  113. if (!limit_value_maybe.has_value()) {
  114. return SQLResult::construct(SQLCommand::Select, SQLErrorCode::SyntaxError, "LIMIT clause must evaluate to an integer value");
  115. }
  116. limit_value = limit_value_maybe.value();
  117. }
  118. size_t offset_value = 0;
  119. if (m_limit_clause->offset_expression() != nullptr) {
  120. auto offset = m_limit_clause->offset_expression()->evaluate(context);
  121. if (!offset.is_null()) {
  122. auto offset_value_maybe = offset.to_u32();
  123. if (!offset_value_maybe.has_value()) {
  124. return SQLResult::construct(SQLCommand::Select, SQLErrorCode::SyntaxError, "OFFSET clause must evaluate to an integer value");
  125. }
  126. offset_value = offset_value_maybe.value();
  127. }
  128. }
  129. context.result->limit(offset_value, limit_value);
  130. }
  131. return context.result;
  132. }
  133. }