8.4.10 SIGN
Returns the sign of the target data (+1 for positive, -1 for negative, 0 for zero).
- Organization of this subsection
(1) Specification format
scalar-function-SIGN ::= SIGN(target-data) target-data ::= value-expression
(2) Explanation of specification format
- target-data:
-
Specifies the numeric data to be processed.
The following rules apply:
-
Specify the target data in the form of a value expression. For details about value expressions, see 7.20 Value expression.
-
Specify numeric data for the target data. For details about numeric data, see (1) Numeric data in 6.2.1 List of data types.
-
You cannot specify a dynamic parameter by itself for the target data.
-
(3) Rules
-
The data type of the execution result is determined based on the data type of the target data, as shown in the following table:
Table 8‒7: Data type of the execution result of the scalar function SIGN No.
Data type of the target data
Data type of the execution result
1
INTEGER
INTEGER
2
SMALLINT
SMALLINT
3
DECIMAL(p,s)
DECIMAL(1,0)
4
DOUBLE PRECISION
DOUBLE PRECISION
-
The NOT NULL constraint does not apply to the value of the execution result (the null value is allowed).
-
If the target data has the null value, the execution result will be a null value.
(4) Example
- Example:
-
Determine whether the values of columns C1 to C3 in table T1 are positive, negative, or zero.
SELECT SIGN("C1"),SIGN("C2"),SIGN("C3") FROM "T1"