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select count(*) from pg_stat_activity where xact_start is not nullAL
IK
check (select exists (select 1 from abstract_table abs where abs.id = id))
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select count(*) from pg_stat_activity where xact_start is not nullAL
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check (select exists (select 1 from abstract_table abs where abs.id = id))
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check (select exists (select 1 from abstract_table abs where abs.id = id))
SELECT 1, достаточно SELECT FROM table, что вернет строки с нулевым кол-вом столбцов.IK
SELECT 1, достаточно SELECT FROM table, что вернет строки с нулевым кол-вом столбцов.P