8.9.2 DAYOFWEEK
Returns the day of the week that the specified date falls on. Note that the first day of the week is Sunday.
- Organization of this subsection
(1) Specification format
scalar-function-DAYOFWEEK ::= {DAYOFWEEK|DOW}(target-data) target-data ::= value-expression
Note: DOW can be used as an abbreviated form for DAYOFWEEK.
(2) Explanation of specification format
- target-data:
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Specifies the data representing the day.
The following rules apply:
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Specify the target data in the form of a value expression. For details about value expressions, see 7.20 Value expression.
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The data type of the target data must be DATE, TIMESTAMP, CHAR, or VARCHAR. In the case of CHAR or VARCHAR, you must specify a character string literal that adheres to the predefined input representation formats. For details about the predefined input representations, see 6.3.3 Predefined character-string representations.
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You cannot specify a dynamic parameter by itself for the target data.
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The following example illustrates the result of executing the scalar function DAYOFWEEK.
- Example
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Return an integer value indicating the day of the week that September 12, 2012 falls on.
DAYOFWEEK(DATE'2012-09-12') → 4
September 12, 2012 is a Wednesday, so it returns 4.
(3) Rules
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The data type of the execution result is INTEGER.
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The NOT NULL constraint does not apply to the value of the execution result (the null value is allowed).
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If the target data has the null value, the execution result will be a null value.
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The relationship between the value of the execution result and the day of the week is shown in the following table.
Table 8‒25: Relationship between the value of the execution result and the day of the week Value of execution result
Day of week
1
Sunday
2
Monday
3
Tuesday
4
Wednesday
5
Thursday
6
Friday
7
Saturday
(4) Example
- Example:
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Return an integer value that indicates the day of the week for the data in column C2 in table T1.
SELECT "C1",DAYOFWEEK("C2") FROM "T1"