ALTER object IF EXISTS
Recorded source states and original language descriptions. Missing version evidence stays unknown.
The source snapshot records transitions for PostgreSQL 8.1–18. The historical matrix records independent cells for 7.4–18. Neither records support for PostgreSQL 19 or 20; newer versions remain unknown. These source claims are distinct from runtime measurements.
No translation of this description is recorded. The original Chinese description is shown.
数据定义语言 (DDL)
Description
许多对象现在支持 ALTER 语句中的 IF EXISTS 子句，例如表、外部表、索引、序列等。
Selected version: PostgreSQL 18
No
Compare versions
Original documentation links
Related source snapshot entry · The original source supplies this relationship; each matrix retains its own states.
Complete source facts and provenance
legacy · center · 6fada67390c2652cfadfaed5774df04335105ed095c3d372faa5367d237a887c
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