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| author | saarni <saarni@gmail.com> | 2016-05-26 10:15:24 -0400 |
|---|---|---|
| committer | Mike Bayer <mike_mp@zzzcomputing.com> | 2016-06-15 14:42:08 -0400 |
| commit | 20f2f5b169d35cfee7cc21ff697e23fd00858171 (patch) | |
| tree | 5c6a893dadb8d64b84b1f89879ffb8fc747d048f /lib/sqlalchemy/sql/compiler.py | |
| parent | 0620a76b582cc93d55e3ddfb74ac22682e148a36 (diff) | |
| download | sqlalchemy-20f2f5b169d35cfee7cc21ff697e23fd00858171.tar.gz | |
Add TABLESAMPLE clause support.
The TABLESAMPLE clause allows randomly selecting an approximate percentage
of rows from a table. At least DB2, Microsoft SQL Server and recent
Postgresql support this standard clause.
Fixes: #3718
Change-Id: I3fb8b9223e12a57100df30876b461884c58d72fa
Pull-request: https://github.com/zzzeek/sqlalchemy/pull/277
Diffstat (limited to 'lib/sqlalchemy/sql/compiler.py')
| -rw-r--r-- | lib/sqlalchemy/sql/compiler.py | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py index 94c7db20a..5e537dfdc 100644 --- a/lib/sqlalchemy/sql/compiler.py +++ b/lib/sqlalchemy/sql/compiler.py @@ -1351,6 +1351,17 @@ class SQLCompiler(Compiled): kw['lateral'] = True return "LATERAL %s" % self.visit_alias(lateral, **kw) + def visit_tablesample(self, tablesample, asfrom=False, **kw): + text = "%s TABLESAMPLE %s" % ( + self.visit_alias(tablesample, asfrom=True, **kw), + tablesample._get_method()._compiler_dispatch(self, **kw)) + + if tablesample.seed is not None: + text += " REPEATABLE (%s)" % ( + tablesample.seed._compiler_dispatch(self, **kw)) + + return text + def get_render_as_alias_suffix(self, alias_name_text): return " AS " + alias_name_text |