## Converting Values

For different application cases, you may need to change how values are represented because the operator used can deal only with a specific representation of values.

### Prerequisites

You require the demo data for the SQL Tutorial.

Start the query tool SQL Studio as database administrator MONA with password RED and log on to the demo database instance DEMODB.

The SQL Reference Manual describes the following functions for these purposes: CHR(a,n), NUM(a), UPPER/LOWER(x), ASCII(x), MAPCHAR(x,n,i), ALPHA(x,n), HEX(a), CHAR(a,t), SOUNDEX(x), VALUE(x,y,...), DECODE(x,y(i),...,z)

### Examples

SELECT * FROM hotel.hotel
WHERE CHR(hno) LIKE '1__'

Displaying the hotel entries whose numbers contain three digits and begin with 1. The hotel number is converted to character values for this purpose.

Result

HNO | NAME | ZIP | ADDRESS
100 | Beach | 32018 | 1980 34th St.
110 | Atlantic | 33441 | 111 78th St.
120 | Long Beach | 90804 | 35 Broadway
130 | Star | 90029 | 13 Beechwood Place
140 | River Boat | 70112 | 788 MAIN STREET
150 | Indian Horse | 92262 | 16 MAIN STREET

See also:

SQL Reference Manual, CHR(a,n)

SELECT * FROM hotel.hotel
WHERE UPPER(name) = 'STAR'

Displaying the hotel name (case insensitive)

Result

HNO | NAME | ZIP | ADDRESS
130 | Star | 90029 | 13 Beechwood Place

See also:

SQL Reference Manual, UPPER/LOWER(x)

SELECT VALUE(firstname, 'Company') firstname, name
FROM hotel.customer
WHERE firstname IS NULL

Displaying the company name; the NULL value is to be replaced by the name Company

Result

FIRSTNAME | NAME
Company | Datasoft
Company | Toolware

See also:

SQL Reference Manual, VALUE(x,y,...)

SELECT hno, price, DECODE(type, 'single', 1, 'double', 2, 'suite', 3) code
FROM hotel.room
WHERE hno < 60

Displaying the hotel rooms with another name for the room types

Result

HNO | PRICE | CODE
10 | 200 | 2
10 | 135 | 1
20 | 100 | 2
20 | 70 | 1
30 | 80 | 2
30 | 45 | 1
40 | 140 | 2
40 | 85 | 1
50 | 180 | 2
50 | 105 | 1
50 | 500 | 3

See also:

SQL Reference Manual, DECODE(x,y(i),...,z)

More examples for Data Query