[gdal-dev] Change in parsing of OGR where clause

[Even Rouault]

Andrew,

> In version 1.X of GDAL, the following was accepted and worked:
> 
> std::string query = "LOCATION=\"some text\"";
> OGR_L_SetAttributeFilter(layer, query.c_str());
> 
> In version 2.X, this is no longer accepted and the double quotes must be
> replaced by single quotes:
> 
> std::string query = "LOCATION='some text'";
> OGR_L_SetAttributeFilter(layer, query.c_str());
> 
> This wouldn't be awful, but the error that occurs tells you nothing about
> the actual problem.  It yields:
> 
> "some text" not recognised as an available field.

Well, I find the message quite clear : "some text" isn't an recognized field :-)

> 
> Perhaps it should give a parsing error?

No, that's valid SQL. "some text" is a quoted identifier, that doesn't match 
any field of your layer.

> In 1.11, parsing the query with
> double quotes would yield an SNT_OPERATION node with subnodes SNT_COLUMN
> and SNT_CONSTANT.  In 2.0, the same query yields an SNT_OPERATION with two
> SNT_COLUMN subnodes, which seems to cause the confusing error.
> 
> Should the parser accept column values with double quotes?  If not, can it
> provide better feedback?

I will stop joking now :-) Here's what you want to read that should explain 
the rationale for this change :
https://trac.osgeo.org/gdal/wiki/rfc52_strict_sql_quoting

Best regards,

Even

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