Application Programming and SQL Guide - Kmlinux

Table 1. Compatibility of data types for assignments and comparisons. Y indicates that the data types are compatible.
N indicates no compatibility. For any number in a column, read the corresponding note at the bottom of the table.
Operands
Binary
integer
Decimal
number
Floating
point
Character
string
Graphic
string
Binary
string Date Time
Time-
stamp
Binary Integer Y Y Y N N N N N N N 2
Decimal
Number
Row
ID
Y Y Y N N N N N N N 2
Floating Point Y Y Y N N N N N N N 2
Character
String
N N N Y Y 4,5
Graphic String N N N Y 4,5
Binary String N N N N 3
N 3
1 1 1 N 2
Y N 1,4 1,4 1,4 N 2
N Y N N N N 2
Date N N N 1 1,4 N Y N N N 2
Time N N N 1 1,4 N N Y N N 2
Timestamp N N N 1 1,4 N N N Y N 2
Row ID N N N N N N N N N Y 2
Distinct Type 2 2 2 2 2 2 2 2 2 2 Y 2
Notes:
Distinct
type
1. The compatibility of datetime values is limited to assignment and comparison:
v Datetime values can be assigned to string columns and to string variables, as explained in Chapter 2 of DB2
SQL Reference.
v A valid string representation of a date can be assigned to a date column or compared to a date.
v A valid string representation of a time can be assigned to a time column or compared to a time.
v A valid string representation of a timestamp can be assigned to a timestamp column or compared to a
timestamp.
2. A value with a distinct type is comparable only to a value that is defined with the same distinct type. In general,
DB2 supports assignments between a distinct type value and its source data type. For additional information, see
Chapter 2 of DB2 SQL Reference.
3. All character strings, even those with subtype FOR BIT DATA, are not compatible with binary strings.
4. On assignment and comparison from Graphic to Character, the resulting length in bytes is 3 * (LENGTH(graphic
string)), depending on the CCSIDs.
5. Character strings with subtype FOR BIT DATA are not compatible with Graphic Data.
Selecting columns: SELECT
You have several options for selecting columns from a database for your result
tables. This section describes how to select columns using a variety of techniques.
Selecting all columns: SELECT *
You do not need to know the column names to select DB2 data. Use an asterisk (*)
in the SELECT clause to indicate that you want to retrieve all columns of each
selected row of the named table.
Example: SELECT *: The following SQL statement selects all columns from the
department table:
SELECT *
FROM DSN8810.DEPT;
The result table looks similar to the following output:
Chapter 1. Retrieving data 5