Database Administration
- postgresql datatypes composite-types
- Updated Thu, 15 Sep 2022 06:45:47 GMT
-
What type of rows does `SELECT my_table FROM my_table` return?
I sometimes encounter this SELECT statement (in JSON-related answers on stackexchanges):
SELECT my_table
FROM my_table;
It seems to turn a one-column result, with multiple rows.
What would be the name of the type of each row returned? A row value of my_table?
(I tried reading the documentation (sql-expressions) but, I could not find a specific answer.)
Solution
It's a named composite type: https://www.postgresql.org/docs/current/static/sql-expressions.html#SQL-SYNTAX-ROW-CONSTRUCTORS
When you create a table, a TYPE with the same name is created.
A row of that table is of that type.
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