fix: allow Limit() without Order() with MSSQL #1009
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query_select.go
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| // Allows Limit() without Order() with MSSQL as per https://stackoverflow.com/a/36156953 | ||
| if q.limit > 0 && fmter.Dialect().Features().Has(feature.OffsetFetch) && len(q.order) == 0 { | ||
| b = append(b, "0 AS _temp_sort, "...) | ||
| q.order = []schema.QueryWithArgs{schema.UnsafeIdent("_temp_sort")} |
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This is query generation and it should not change the original SelectQuery, because someone may be reusing them.
You probably need to add another block of code to generate order without changing the SelectQuery.
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Do you mean that if I have a SelectQuery in a variable a and then do b := a.Limit(5), the value of a would change, and that would be a problem? Isn't that also the case without the proposed change? I cannot seem to find an analog for this case to compare to. Do you mean something like ORDER BY after LIMIT, or is there another case where there could be something appended to a select query after Limit()? An example would be much appreciated.
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@CL-Jeremy I've fixed this myself. See the commits in this branch.
Implements workaround from https://stackoverflow.com/a/36156953 for all backends supporting
feature.OffsetFetchfrom ISO/ANSI SQL:2008, which specifiesORDER BYas a requirement. This should be tested further if more backends are to be added (such as Oracle in #995 – this feature is not enable there, and there seems to be an impact noted by https://stackoverflow.com/q/48620590 and https://stackoverflow.com/q/59864964).Closes #811