ansi-sql

I have the following medleys table that combines colors , fruits and ratings : [medleys] medley_id | color | fruit | rating ============================================== 1 red apple 25 2 blue pear 5 3 green apple 12 4 red apple 10 5 purple kiwi 5 6 purple kiwi 50 7 blue kiwi 3 8 blue pear 9 I am trying to write an ANSI-compliant SQL query that will combine every unique/distinct color - fruit pair and sum each pair's individual rating values. Thus if you ran the query on the table above it would produce the following result sets: [query] color | fruit | sum =========================== red

I need a way to determine the number of days between two dates in SQL. Answer must be in ANSI SQL. Monkey Boson ANSI SQL-92 defines DATE - DATE as returning an INTERVAL type. You are supposed to be able to extract scalars from INTERVALS using the same method as extracting them from DATEs using – appropriately enough – the EXTRACT function (4.5.3). <extract expression> operates on a datetime or interval and returns an exact numeric value representing the value of one component of the datetime or interval. However, this is very poorly implemented in most databases. You're probably stuck using

This has always bothered me - why does the GROUP BY clause in a SQL statement require that I include all non-aggregate columns? These columns should be included by default - a kind of "GROUP BY *" - since I can't even run the query unless they're all included. Every column has to either be an aggregate or be specified in the "GROUP BY", but it seems like anything not aggregated should be automatically grouped. Maybe it's part of the ANSI-SQL standard, but even so, I don't understand why. Can somebody help me understand the need for this convention? It's hard to know exactly what the designers

In MS Sql Server is easy create autoincrement fields. In my systems I stopped to use autoincrement fields for primary keys, and now I use Guid's. It was awesome, I've got a lot of advantages with that change. But in another non-primary key fields, I really was needing implement a "soft autoincrement". It's because my system is DB independent, so I create the autoinc value programatically in c#. I would like about solutions for autoincrement fields on databases without autoincrement, what the solution that your use and why? There is some Sql Ansi statement about this? and generating directly

What does || do in SQL? SELECT 'a' || ',' || 'b' AS letter collapsar || represents string concatenation. Unfortunately, string concatenation is not completely portable across all sql dialects: ansi sql: || (infix operator) mysql: concat ( vararg function ). caution : || means 'logical or' ( It's configurable , however; thanks to @hvd for pointing that out) oracle: || (infix operator), concat ( caution : function of arity 2 only ! ) postgres: || (infix operator) sql server: + (infix operator), concat ( vararg function ) sqlite: || (infix operator) hopefully the confusion is complete ... John

Can anyone recommend a good ANSI SQL reference manual? I don't necessary mean a tutorial but a proper reference document to lookup when you need either a basic or more in-depth explanation or example. Currently I am using W3Schools SQL Tutorial and SQL Tutorial which are ok, but I don't find them "deep" enough. Of course, each major RDBMS producer will have some sort of reference manuals targeting their own product, but they tend to be biased and sometime will use proprietary extensions. EDITED: The aim of the question was to focus on the things database engines have in common i.e. the SQL