Question

I’m doing a program in C# (windows forms) and SQL-Server where I need to take the strings from two columns and put them into an array. I will use that array later in order to implement autocomplete to some textBoxes. The rules are:

• The array should be able to hold whatever the amount of strings I
  have in the columns, this amount may exceed 500 strings and is variable.
• I will need the distinct values from the columns, no duplicates.

I think I’m supposed to use “UNION” for putting together all the strings from the two columns and SqlDataReader with a “while” cycle when putting the strings into the array.

Here is an example table, use it to explain it to me:

----------------------------
|    name    |   surname   |
----------------------------
|    John    |   Jackson   |
----------------------------
|   Michael  |    Jones    |
----------------------------
|   Amanda   |    Lopez    |
----------------------------
|  Christina |    Lopez    |
----------------------------

So how would the query look like and how would can I put the results into an array?

Answer 1

If you want a concatenate use this:

SELECT DISTINCT name + surname FROM MyTable

If you dont want a concatenate you can do this:

   SELECT Col1 FROM MyTable
    UNION
    SELECT Col2 FROM MyTable

A union will work as long as Col1 and Col2 have the same datatype. Once you have the data you can bring it back to the client side (via a sproc) into a dataset, datatable, or sqldatareader.

The rest should be simple, take the data and store it in an array of some sort.
Either through some sort of loop

reader = GetData();
while(reader.read())
 {
  //store into an array...
 }

Copy paste this in sql server management studio

CREATE TABLE #Test
(
 col1 varchar(10),
 col2 varchar(10)
)

INSERT INTO #Test(col1, col2) VALUES('jon', 'jane')
INSERT INTO #Test(col1, col2) VALUES('jane', 'jane')
INSERT INTO #Test(col1, col2) VALUES('bob', 'phil')
INSERT INTO #Test(col1, col2) VALUES('marc', 'phil')
INSERT INTO #Test(col1, col2) VALUES('jon', 'jon')
INSERT INTO #Test(col1, col2) VALUES('jon', 'Jon')
INSERT INTO #Test(col1, col2) VALUES('jane1', 'jane')
INSERT INTO #Test(col1, col2) VALUES('bob2', 'phil')
INSERT INTO #Test(col1, col2) VALUES('marc2', 'phil')
INSERT INTO #Test(col1, col2) VALUES('ste', 'jane')

SELECT col1 FROM #test
UNION
SELECT col2 FROM #test

DROP TABLE #Test

The result is:

bob
bob2
jane
jane1
jon
marc
marc2
phil
ste