Question

Ok, I am learning SQL and just installed SQL Server. I’ve read about outer joins and inner joins but am not sure either is what I want. Basically, I want to reconstruct a text file that has been “chopped” up into 5 smaller text files. The columns are the same across all 5 text files, e.g. name, age, telephone #, etc. The only difference is that they have different numbers of rows of data.

What I’d like to do is “append” the data from each file into one “mega-file”. Should I create a table containing all of the data, or just create a view? Then, how do I implement this…do I use union? Any guidance would be appreciated, thanks.

Answer 1

Beyond your immediate goal of merging the five files it sounds like you want the data contained in your text files to be generally available for more flexible analysis.

An example of why you might require this is if you need to merge other data with the data in your text files. (If this is not the case then Oded is right on the money, and you should simply use logparser or Visual Log Parser.)

Since your text files all contain the same columns you can insert them into one table*.

1. Issue a CREATE statement defining your table
2. Insert data into your newly created table**
3. Create an index on field(s) which might often be used in query predicates
4. Write a query or create a view to provide the data you need

*Once you have your data in a table you can think about creating views on the table, but to start you might just run some ad hoc queries.

**Note that it is possible to accomplish Step 2 in other ways. Alternatively you can programmatically construct and issue your INSERT statements.

Examples of each of the above steps are included below, and a tested example can be found at: http://sqlfiddle.com/#!6/432f7/1

-- 1.
CREATE TABLE mytable 
    (
     id int identity primary key, 
     person_name varchar(200), 
     age integer,
     tel_num varchar(20)
    );

-- 2. or look into BULK INSERT option https://stackoverflow.com/q/11016223/42346
INSERT INTO mytable
    (person_name, age, tel_num)
VALUES
    ('Jane Doe', 31, '888-888-8888'),
    ('John Smith', 24, '888-555-1234');

-- 3.
CREATE UNIQUE INDEX mytable_age_idx ON mytable (age);

-- 4.
SELECT id, person_name, age, tel_num
FROM mytable
WHERE age < 30;