Saved Queries

Choose Columns

A view can output fewer columns than the base table.

highlighted = computed this step

Choose columns

A view can show fewer columns than the base table.

choose columns\text{choose columns}

Show the smaller shape

The output has 2 columns across 3 rows.

columns=2\text{columns}=2

View examples are tiny finite saved-query outputs; SQL dialects, optimizers, security, updatability, materialized-view strategy, performance, and maintenance advice are out of scope.

Choose columns: base tableidstatustotal1open502closed203open70 view column mappingsourceoutputididtotaltotal view filteropcolumnvaluenonenonenone source rows usedbaseRow012 current view outputidtotal150220370 view factsfactvaluebaseRowCount3sourceRowCount3rowCount3columnCount2stalenot_materializedhasFilternohasAliasesnohasMaterializedCopyno

Read the mapping

The column-mapping table shows which base columns became output columns.

source to output\text{source to output}

Summary

Column choice changes the view shape, not the base table.

base stays put\text{base stays put}