Cross Joins

Qualified Output Columns

Qualified labels keep both sides readable.

highlighted = computed this step

Qualified output columns

When both sides have a column with the same name, the output labels keep the side visible.

qualified names\text{qualified names}

Read output shape

The output has 4 qualified columns across 4 rows.

columns=4\text{columns}=4

CROSS JOIN examples are tiny finite-table transforms; SQL dialect completeness, type coercion, optimizer behavior, execution cost, indexing, and database-product claims are out of scope.

Qualified output columns: left tableidname1Ada2Ben Qualified output columns: right tableidroom10lab20hall pair gridleftSourcerightSourceleftValuesrightValuesoutput00[1, Ada][10, lab][1, Ada, 10, lab]01[1, Ada][20, hall][1, Ada, 20, hall]10[2, Ben][10, lab][2, Ben, 10, lab]11[2, Ben][20, hall][2, Ben, 20, hall] CROSS JOIN output rowsleft.idleft.nameright.idright.room1Ada10lab1Ada20hall2Ben10lab2Ben20hall CROSS JOIN factsfactvalueleftRowCount2rightRowCount2pairCount4outputRowCount4outputColumnCount4rowOrderleft_source_then_right_sourceemptySideProductno

Names stay readable

The renderer labels columns as left dot name and right dot name.

left dot right dot\text{left dot right dot}

Summary

Qualification here is a teaching display convention, not a product SQL claim.

visible sides\text{visible sides}