Robert Schulze 366f368d06

Disallow LIKE patterns with trailing escape ...

Trailing escape ('ab\') is disallowed in SQL, in standardese:

  "If an escape character is specified, then [...] If there is not a
  partitioning of the string PVC into substrings such that each substring
  has length 1 (one) or 2, no substring of length 1 (one) is the escape
  character ECV, and each substring of length 2 is the escape character
  ECV followed by either the escape character ECV, an <underscore>
  character, or the <percent> character, then an exception condition is
  raised: data exception - invalid escape sequence."

I first thought this is checked already higher up in the stack, at least
for const needles, as single trailing backslashes ('ab\') are rejected,
but then I realized that ClickHouse quotes by default. I.e., double
trailing backslashes ('ab\\') are not rejected but when interpreted as
LIKE needle ('ab\') they should.

2022-06-01 21:38:46 +02:00

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