"||" 和有什么不一样 Oracle 中的运算符和 concat 函数？
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What is the difference between "||" operator and concat function in Oracle?
提问by Java SE
Would it be possible to explain the difference between the concat()function and the ||operator in Oracle?
能否解释一下Oracle 中concat()函数和||运算符之间的区别？
Which one is better in terms of performance?
哪个在性能方面更好？
回答by Justin Cave
There is no functional difference.
没有功能差异。
||is the ANSI standard string concatenation operator (though, unfortunately, not every database <cough>SQL Server</cough>chooses to support the standard). Many databases support a CONCATfunction so it may be easier to port code using CONCATto different databases.
||是 ANSI 标准字符串连接运算符（但不幸的是，并非每个数据库都<cough>SQL Server</cough>选择支持该标准）。许多数据库都支持一个CONCAT函数，因此将代码移植CONCAT到不同的数据库可能会更容易。
回答by rahul
'concat' function can be operated only on 2 variables or columns, while 'concat' operation can be done for any number of variables or columns.
'concat' 函数只能对 2 个变量或列进行操作，而 'concat' 操作可以对任意数量的变量或列进行。
