Issue queries

Here you are shown how to issue queries without using a table.

This is done in different ways across different platforms but all of them will give a single row of information.

schema:scott

Only certain functions can be used without a table and these functions are called static functions.

Static functions can allow a user to obtain the current username, current date, current timestamp and also the version of the database being used.

SELECT CURRENT_USER, CURRENT_DATE

SELECT USER, CURRENT_DATE FROM dual

SELECT SYSTEM_USER, GETDATE()

SELECT ENVIRON('username'), Date()

For oracle you can use:

SELECT USER, CURRENT_DATE, CURRENT_TIMESTAMP, (SELECT banner FROM v$version WHERE ROWNUM = 1), DBMS_RANDOM.RANDOM(), SYS_GUID()

FROM dual

For mysql you can use:

SELECT CURRENT_USER, CURRENT_DATE, CURRENT_TIMESTAMP,

VERSION(), RAND(), UUID()

For sqlserver you can use:

SELECT SYSTEM_USER, CAST(CAST(GetDate() AS INT) AS DATETIME),

GetDate(), @@VERSION, RAND(), NEWID()

For postgres you can use:

SELECT CURRENT_USER, CURRENT_DATE, CURRENT_TIMESTAMP,

VERSION(), RANDOM()

In access you have to create a new database,

then create a query in that database and then run the function given in the example in SQL view.

SQL HACKS

Hack 10 Converting subqueries into joins

Hack 11 Converting aggregate subqueries into joins

Hack 14 Generate Combinations

Hack 16 Search for a String across columns

Hack 24 Multiply Across a Result Set

Hack 25 Keep a running total

Hack 25.5 Splitting and combining columns

Hack 26 Include the rows your JOIN forgot

Hack 30 Calculate the maximum/minimum of two fields

Hack 33 Get values and subtotals in one shot

Hack 50 Combine tables containing different data

Hack 51/52 Display rows as columns

Hack 55 Import Someone Else's Data

Hack 62 Issue Queries Without Using a Table

Hack 63 Generate rows without tables

Hack 70 Combine your queries

Hack 72 Extract a subset of the results

Hack 78 Break it down by Range

Hack 88 Test two values from a subquery

Hack 98 Find and stop long running queries

Hack 100 Run SQL from a Web Page