Postgresql updating millions of rows
That's the reason why this chapter still is necessary. Sometimes CONNECT BY is used as a simple iterator: This exceptions are disabled by default for selects in PLpg SQL.You need to add keyword STRICT after any keyword INTO in all selects, when You need to keep single row checking in stored PLpg SQL code. Postgres sticks mostly to SQL standards while Oracle in history choose it's own way - especially concerning data types.
FLOAT (Oracle) is REAL (Postgres) and DOUBLE is DOUBLE PRECISION Oracle mostly uses the data type DATE which is a combination of date time.In case you need to include a sequence's value in a more complex SQL statement, you can use [db_sequence_nextval_sql sequence_name] which will return the appropriate grammar.Oracle's handy decode function works as follows: To evaluate this expression, Oracle compares expr to each search value one by one.In Oracle empty strings () and NULL values in string context are the same till latest versions.You can concatenate NULL result with a string and obtain this string as result. In Oracle You need use IS NULL operator to check whether string is empty.
Postgres (and Oracle) has a function that performs the same thing in a more generalized way: coalesce(expr1, expr2, expr3,....) returns the first non-null expression that is passed to it.