37d6d07dda
This restores a parse error that was thrown (though only in the ORDER BY case) by the original collation patch. I had removed it in my recent revisions because it was thrown at a place where collations now haven't been computed yet; but I thought of another way to handle it. Throwing the error at parse time, rather than leaving it to be done at runtime, is good because a syntax error pointer is helpful for localizing the problem. We can reasonably assume that the comparison function for a collatable datatype will complain if it doesn't have a collation to use. Now the planner might choose to implement GROUP or DISTINCT via hashing, in which case no runtime error would actually occur, but it seems better to throw error consistently rather than let the error depend on what the planner chooses to do. Another possible objection is that the user might specify a nondefault sort operator that doesn't care about collation ... but that's surely an uncommon usage, and it wouldn't hurt him to throw in a COLLATE clause anyway. This change also makes the ORDER BY/GROUP BY/DISTINCT case more consistent with the UNION/INTERSECT/EXCEPT case, which was already coded to throw this error even though the same objections could be raised there. |
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| .. | ||
| .gitignore | ||
| Makefile | ||
| README | ||
| analyze.c | ||
| gram.y | ||
| keywords.c | ||
| kwlookup.c | ||
| parse_agg.c | ||
| parse_clause.c | ||
| parse_coerce.c | ||
| parse_collate.c | ||
| parse_cte.c | ||
| parse_expr.c | ||
| parse_func.c | ||
| parse_node.c | ||
| parse_oper.c | ||
| parse_param.c | ||
| parse_relation.c | ||
| parse_target.c | ||
| parse_type.c | ||
| parse_utilcmd.c | ||
| parser.c | ||
| scan.l | ||
| scansup.c | ||
README
src/backend/parser/README Parser ====== This directory does more than tokenize and parse SQL queries. It also creates Query structures for the various complex queries that are passed to the optimizer and then executor. parser.c things start here scan.l break query into tokens scansup.c handle escapes in input strings kwlookup.c turn keywords into specific tokens keywords.c table of standard keywords (passed to kwlookup.c) gram.y parse the tokens and produce a "raw" parse tree analyze.c top level of parse analysis for optimizable queries parse_agg.c handle aggregates, like SUM(col1), AVG(col2), ... parse_clause.c handle clauses like WHERE, ORDER BY, GROUP BY, ... parse_coerce.c handle coercing expressions to different data types parse_collate.c assign collation information in completed expressions parse_cte.c handle Common Table Expressions (WITH clauses) parse_expr.c handle expressions like col, col + 3, x = 3 or x = 4 parse_func.c handle functions, table.column and column identifiers parse_node.c create nodes for various structures parse_oper.c handle operators in expressions parse_param.c handle Params (for the cases used in the core backend) parse_relation.c support routines for tables and column handling parse_target.c handle the result list of the query parse_type.c support routines for data type handling parse_utilcmd.c parse analysis for utility commands (done at execution time)