Progress/ESQL Extensions to 1989 SQL
The standard explicitly forbids the following Progress/ESQL extensions:
- GROUP BY <scalar expression> — SQL 89 allows only a column reference.
NOTE: SQL 89 prohibits this if the subquery is part of a comparison predicate; Progress allows this.- GROUP BY or HAVING in <subquery>.
NOTE: Progress/ESQL allows this if the query does not contain a clause (GROUP BY, DISTINCT, UNION, etc.) that causes the cursor to use a temporary result table.- ORDER BY column not in <select list>.
- ORDER BY <scalar expression> — SQL 89 allows only a column reference.
NOTE: Progress/ESQL cursors with ORDER BY are updatable unless the cursor uses a temporary result table.- ORDER BY and cursors — SQL 89 ORDER BY cursors are read only.
- ORDER BY in <subquery>.
NOTE: Although multiple-character string literals are allowed, only the first character is used.- ESCAPE character in LIKE predicate — SQL 89 allows only a single-character literal.
NOTE: You may repeat a table name in a FROM clause without a correlation name. The duplicate is ignored.- Table name repeated in FROM clause.
- DISTINCT specified more than once in a subquery.
- Updatable query expression with a subquery.
- DISTINCT set function as an operand of a dyadic operator.
- INSERT . . . SELECT specifies the same table for INTO as SELECT.
- DELETE FROM <table> WHERE specifies <table> in a subquery.
- UPDATE specifies same column more than once in SET list.
- SELECT INTO with GROUP BY.
- SELECT INTO with HAVING.
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