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| author | Tomas Vondra <tomas.vondra@postgresql.org> | 2019-01-19 23:48:16 +0100 |
|---|---|---|
| committer | Tomas Vondra <tomas.vondra@postgresql.org> | 2019-01-20 00:22:14 +0100 |
| commit | 31f3817402da736b29014ace470cf70aeb126ac5 (patch) | |
| tree | ab02bcacacdb944f47996f10435a94c9f0258543 /src/backend/parser/parse_expr.c | |
| parent | d6ef7fe75c1fb7ccc4ad8e3dd38d4e84d6fe9b9f (diff) | |
| download | postgresql-31f3817402da736b29014ace470cf70aeb126ac5.tar.gz postgresql-31f3817402da736b29014ace470cf70aeb126ac5.zip | |
Allow COPY FROM to filter data using WHERE conditions
Extends the COPY FROM command with a WHERE condition, which allows doing
various types of filtering while importing the data (random sampling,
condition on a data column, etc.). Until now such filtering required
either preprocessing of the input data, or importing all data and then
filtering in the database. COPY FROM ... WHERE is an easy-to-use and
low-overhead alternative for most simple cases.
Author: Surafel Temesgen
Reviewed-by: Tomas Vondra, Masahiko Sawada, Lim Myungkyu
Discussion: https://www.postgresql.org/message-id/flat/CALAY4q_DdpWDuB5-Zyi-oTtO2uSk8pmy+dupiRe3AvAc++1imA@mail.gmail.com
Diffstat (limited to 'src/backend/parser/parse_expr.c')
| -rw-r--r-- | src/backend/parser/parse_expr.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index bff237094ad..a47697a4215 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -1849,6 +1849,9 @@ transformSubLink(ParseState *pstate, SubLink *sublink) case EXPR_KIND_CALL_ARGUMENT: err = _("cannot use subquery in CALL argument"); break; + case EXPR_KIND_COPY_WHERE: + err = _("cannot use subquery in COPY FROM WHERE condition"); + break; /* * There is intentionally no default: case here, so that the @@ -3475,6 +3478,8 @@ ParseExprKindName(ParseExprKind exprKind) return "PARTITION BY"; case EXPR_KIND_CALL_ARGUMENT: return "CALL"; + case EXPR_KIND_COPY_WHERE: + return "WHERE"; /* * There is intentionally no default: case here, so that the |