PostgreSQL-"IN"中参数的最大数量条款? [英] PostgreSQL - max number of parameters in "IN" clause?

问题描述

在Postgres中，您可以指定一个IN子句，如下所示:

In Postgres, you can specify an IN clause, like this:

SELECT * FROM user WHERE id IN (1000, 1001, 1002)

有人知道您可以传入IN的最大参数数量是多少吗?

Does anyone know what's the maximum number of parameters you can pass into IN?

推荐答案

根据位于

According to the source code located here, starting at line 850, PostgreSQL doesn't explicitly limit the number of arguments.

以下是第870行的代码注释:

The following is a code comment from line 870:

/*
 * We try to generate a ScalarArrayOpExpr from IN/NOT IN, but this is only
 * possible if the inputs are all scalars (no RowExprs) and there is a
 * suitable array type available.  If not, we fall back to a boolean
 * condition tree with multiple copies of the lefthand expression.
 * Also, any IN-list items that contain Vars are handled as separate
 * boolean conditions, because that gives the planner more scope for
 * optimization on such clauses.
 *
 * First step: transform all the inputs, and detect whether any are
 * RowExprs or contain Vars.
 */

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