SQL: extending the grammar

[astefan]

• at the moment we support FIRST/LAST functions which have an equivalent meaning with MIN/MAX for String fields. We should allow MIN/MAX for strings and delegate to FIRST/LAST functions.
• TRUNC/TRUNCATE function is available in many RDBs. We support this one in the TRUNCATE form, but Oracle, Postgresql supports the TRUNC variant. We should consider simply adding an alias for the already available TRUNCATE function.
• ATAN2(param1, param2) should be equivalent to ATAN(param1 / param2) called with two parameters and MySQL allows the ATAN function to receive one or two parameters.
• maybe consider adding a TRIM(param) function that should be the equivalent of LTRIM(RTRIM(param)).

[elasticmachine]

Pinging @elastic/es-search

[costin]

Adding to the list

• TOP - as a synonym to LIMIT