7.27.2 Data types of the results of concatenation operations

The data type of the result of a concatenation operation is determined by the data types of the first and second operands.

Organization of this subsection

(1) If the data type of the operand is character string data
(2) When the operands are binary data

(1) If the data type of the operand is character string data

The following table shows the relationship between the data type of the operands and the data type of the result of the operation (if the data type of the operand is character string data).

Table 7‒48: Relationship between the data type of the operands and the data type of the result of the operation (if the data type of the operand is character string data)
Data type and data length of the first operand	Data type and data length of the second operand	Data type and data length of the operation result
CHAR(`m`)	CHAR(`n`)	CHAR(`m`+`n`)
	VARCHAR(`n`) Data length: `L2`	If `m` + `n` ≤ 32,000 VARCHAR(`m`+`n`) Actual data length: `m` + `L2` If `m` + `n` > 32,000 STRING Actual data length: `m` + `L2`
	STRING Data length: `L2`	STRING Actual data length: `m` + `L2`
VARCHAR(`m`) Actual data length: `L1`	CHAR(`n`)	If `m` + `n` ≤ 32,000 VARCHAR(`m`+`n`) Actual data length: `L1` + `n` If `m` + `n` > 32,000 STRING Actual data length: `L1` + `n`
	VARCHAR(`n`) Data length: `L2`	If `m` + `n` ≤ 32,000 VARCHAR(`m`+`n`) Actual data length: `L1` + `L2` If `m` + `n` > 32,000 STRING Actual data length: `L1` + `L2`
	STRING Data length: `L2`	STRING Actual data length: `L1` + `L2`
STRING Actual data length: `L1`	CHAR(`n`)	STRING Actual data length: `L1` + `n`
	VARCHAR(`n`) Data length: `L2`	STRING Actual data length: `L1` + `L2`
	STRING Data length: `L2`	STRING Actual data length: `L1` + `L2`

Legend:

m: Maximum data length of the first operand

n: Maximum data length of the second operand

L1: Actual data length of the data of the first operand

L2: Actual data length of the data of the second operand

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(2) When the operands are binary data

The following table shows the relationship between the data types of the operands and the data type of the result of the operation when the operands are binary data.

Table 7‒49: Relationship between the data types of the operands and the data type of the result of the operation (when the operands are binary data)
No.	Data type and data length of the first operand	Data type and data length of the second operand	Data type and data length of the result of the operation
1	BINARY(`m`)	BINARY(`n`)	BINARY(`m`+`n`)
2	BINARY(`m`)	VARBINARY(`n`) Actual data length: `L2`	VARBINARY(`m`+`n`) Actual data length: `m`+`L2`
3	VARBINARY(`m`) Actual data length: `L1`	BINARY(`n`)	VARBINARY(`m`+`n`) Actual data length: `L1`+`n`
4	VARBINARY(`m`) Actual data length: `L1`	VARBINARY(`n`) Actual data length: `L2`	VARBINARY(`m`+`n`) Actual data length: `L1`+`L2`

Legend:

m: Maximum length of the data in the first operand

n: Maximum length of the data in the second operand

L1: Actual data length of the data in the first operand

L2: Actual data length of the data in the second operand

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