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

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.

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.

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"

[Figure]