AddExpressionCloser returns a new iterator that ensures that any expressions that implement sql.Closer are closed.

GetColumnsAndPrepareExpressions extracts the unique columns required by all those expressions and fixes the indexes of the GetFields in the expressions to match a row with only the returned columns in that same order.

NewMergeJoin returns a node that performs a presorted merge join on two relations.

ProjectRow evaluates a set of projections.

ErrTableNotLockable is returned whenever a lockable table can't be found.

BaseBuilder converts a plan tree into a RowIter tree.

FulltextFilterTable handles row iteration for filters involving Full-Text indexes, as they behave differently than other indexes.