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ShowColumns Unary Command

ShowColumns is a UnaryCommand (and a Logical Command) that represents SHOW COLUMNS SQL statement in logical query plans.

Creating Instance

ShowColumns takes the following to be created:

ShowColumns is created when:

Output Schema

ShowColumns can be given output Attributes when created.

The output schema is by default as follows:

Column Name Data Type Nullable
col_name StringType

Logical Analysis

ShowColumns is resolved to ShowColumnsCommand logical runnable command by ResolveSessionCatalog logical resolution rule.

Query Planning

DataSourceV2Strategy throws an AnalysisException for ShowColumnss in query plans.