sql

sql

SELECT + JOIN

I learned SQL (basic and quite advanced stuff) at the univerity a few years ago. I’ve been using SQL commands quite often; it’s difficult to imagine an application or a web page without a database in the back-end.

Recently, I’ve discovered I remember little about using JOIN command in SELECTs. There are a few types of JOINs; however, I’ve been …

Summary of Communities to Communities (C2C) 2009 Conference

C2C is a history now. I attended .NET stream and one session on SQL. The conference as a whole was very interesting, well organised, and basically developing. It was a Polish conference so most sessions were conducted in Polish but there were a couple of speakers from abroad too, and they spoke in English.

Basically I’m happy I had a …

SQL: CONVERT to DATETIME

I’ve heard that SQL Server developers happen to have problems with CONVERT function when try to obtain a value of datetime type. Recently, I’ve had that problem during a Data Transformation Services (DTS) package implementation.

One of the task in that package was “Transform Data”, which transferred data between a source and destination. To retrieve that data, I used SQL …

TSQL – How to select multiple rows into a single row

I spend too long on finding the solution for this problem…

Basically I had a table which looked like this
table-9146579

What I wanted was to select all as one row as a set of items separated with a comma, where an item was ‘id: name’. The items had to be sorted by the id. So the result was supposed to …

Exception – ORA-00604: error occurred at recursive SQL level 1 ORA-01003: no statement parsed

In my application data were collected from database (Oracle) using web services that called stored procedures. One of the stored procedure had SELECT defined similar to the one below:

WITH sth1 as 
(
        SELECT ...
),
sth2 as 
(
        SELECT ...
)
SELECT ...

This construction was the reason why in my application I was getting the following exception while …