What does SQL Select symbol || mean?

|| represents string concatenation. Unfortunately, string concatenation is not completely portable across all sql dialects:

  • ansi sql: || (infix operator)
  • mysql: concat ( vararg function ). caution: || means ‘logical or’ (It’s configurable, however; thanks to @hvd for pointing that out)
  • oracle: || (infix operator), concat ( caution: function of arity 2 only ! )
  • postgres: || (infix operator)
  • sql server: + (infix operator), concat ( vararg function )
  • sqlite: || (infix operator)

hopefully the confusion is complete …

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