Postgres 16

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/* Here, the resultset returned from `generate_series(1,3)` has the name `generate_series` with a single column also named `generate_series`: */
SELECT
  *
FROM
  generate_series(1,5);

generate_series

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SELECT 5

/* When `AS q` is used like a table-alias `q` it actually renames both the returned table _and_ the column to the same name: */
SELECT
  this_is_actually_the_column_name,
  this_is_actually_the_column_name.*  /* <-- I don't know why this is allowed... */
FROM
  generate_series(1,5) AS this_is_actually_the_column_name;

this_is_actually_the_column_name
this_is_actually_the_column_name

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5

SELECT 5

/* This shows the column being renamed without needing to give an alias to the function's resultset: */
SELECT
  generate_series AS columnNameGoesHere
FROM
  generate_series(1,5);

columnnamegoeshere

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SELECT 5

/* This shows the column being renamed while also giving an alias to the function's resultset: */
SELECT
  generated_table_name.colName
FROM
  generate_series(1,5) AS generated_table_name( colName );

colname

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SELECT 5