func (p *planner) fillDefaults(
	defaultExprs []parser.TypedExpr, cols []sqlbase.ColumnDescriptor, n *parser.Insert,
) (parser.SelectStatement, error) {
	if n.DefaultValues() {
		row := make(parser.Exprs, 0, len(cols))
		for i := range cols {
			if defaultExprs == nil {
				row = append(row, parser.DNull)
				continue
			}
			row = append(row, defaultExprs[i])
		}
		return &parser.ValuesClause{Tuples: []*parser.Tuple{{Exprs: row}}}, nil
	}

	values, ok := n.Rows.Select.(*parser.ValuesClause)
	if !ok {
		return n.Rows.Select, nil
	}

	ret := values
	for tIdx, tuple := range values.Tuples {
		tupleCopied := false
		for eIdx, val := range tuple.Exprs {
			switch val.(type) {
			case parser.DefaultVal:
				if !tupleCopied {
					if ret == values {
						ret = &parser.ValuesClause{Tuples: append([]*parser.Tuple(nil), values.Tuples...)}
					}
					ret.Tuples[tIdx] =
						&parser.Tuple{Exprs: append([]parser.Expr(nil), tuple.Exprs...)}
					tupleCopied = true
				}
				if defaultExprs == nil || eIdx >= len(defaultExprs) {
					// The case where eIdx is too large for defaultExprs will be
					// transformed into an error by the check on the number of
					// columns in Insert().
					ret.Tuples[tIdx].Exprs[eIdx] = parser.DNull
				} else {
					ret.Tuples[tIdx].Exprs[eIdx] = defaultExprs[eIdx]
				}
			}
		}
	}
	return ret, nil
}

// Insert inserts rows into the database.
// Privileges: INSERT on table. Also requires UPDATE on "ON DUPLICATE KEY UPDATE".
//   Notes: postgres requires INSERT. No "on duplicate key update" option.
//          mysql requires INSERT. Also requires UPDATE on "ON DUPLICATE KEY UPDATE".
func (p *planner) Insert(
	n *parser.Insert, desiredTypes []parser.Type, autoCommit bool,
) (planNode, error) {
	tn, err := p.getAliasedTableName(n.Table)
	if err != nil {
		return nil, err
	}

	en, err := p.makeEditNode(tn, autoCommit, privilege.INSERT)
	if err != nil {
		return nil, err
	}
	if n.OnConflict != nil {
		if !n.OnConflict.DoNothing {
			if err := p.checkPrivilege(en.tableDesc, privilege.UPDATE); err != nil {
				return nil, err
			}
		}
		// TODO(dan): Support RETURNING in UPSERTs.
		if n.Returning != nil {
			return nil, fmt.Errorf("RETURNING is not supported with UPSERT")
		}
	}

	var cols []sqlbase.ColumnDescriptor
	// Determine which columns we're inserting into.
	if n.DefaultValues() {
		cols = en.tableDesc.Columns
	} else {
		var err error
		if cols, err = p.processColumns(en.tableDesc, n.Columns); err != nil {
			return nil, err
		}
	}
	// Number of columns expecting an input. This doesn't include the
	// columns receiving a default value.
	numInputColumns := len(cols)

	colIDSet := make(map[sqlbase.ColumnID]struct{}, len(cols))
	for _, col := range cols {
		colIDSet[col.ID] = struct{}{}
	}

	// Add the column if it has a DEFAULT expression.
	addIfDefault := func(col sqlbase.ColumnDescriptor) {
		if col.DefaultExpr != nil {
			if _, ok := colIDSet[col.ID]; !ok {
				colIDSet[col.ID] = struct{}{}
				cols = append(cols, col)
			}
		}
	}

	// Add any column that has a DEFAULT expression.
	for _, col := range en.tableDesc.Columns {
		addIfDefault(col)
	}
	// Also add any column in a mutation that is WRITE_ONLY and has
	// a DEFAULT expression.
	for _, m := range en.tableDesc.Mutations {
		if m.State != sqlbase.DescriptorMutation_WRITE_ONLY {
			continue
		}
		if col := m.GetColumn(); col != nil {
			addIfDefault(*col)
		}
	}

	defaultExprs, err := makeDefaultExprs(cols, &p.parser, &p.evalCtx)
	if err != nil {
		return nil, err
	}

	// Replace any DEFAULT markers with the corresponding default expressions.
	insertRows, err := p.fillDefaults(defaultExprs, cols, n)
	if err != nil {
		return nil, err
	}

	// Analyze the expressions for column information and typing.
	desiredTypesFromSelect := make([]parser.Type, len(cols))
	for i, col := range cols {
		desiredTypesFromSelect[i] = col.Type.ToDatumType()
	}

	// Create the plan for the data source.
	// This performs type checking on source expressions, collecting
	// types for placeholders in the process.
	rows, err := p.newPlan(insertRows, desiredTypesFromSelect, false)
	if err != nil {
		return nil, err
	}

	if expressions := len(rows.Columns()); expressions > numInputColumns {
		return nil, fmt.Errorf("INSERT error: table %s has %d columns but %d values were supplied", n.Table, numInputColumns, expressions)
	}
//.........这里部分代码省略.........