Help Center/ GaussDB/ Developer Guide(Distributed_V2.0-3.x)/ System Catalogs and System Views/ System Views/ MY_TAB_COL_STATISTICS
Updated on 2025-08-19 GMT+08:00
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MY_TAB_COL_STATISTICS

MY_TAB_COL_STATISTICS displays column statistics and histogram information extracted from MY_TAB_COLUMNS. All users can access this view. This view exists in both PG_CATALOG and SYS schema.

Table 1 MY_TAB_COL_STATISTICS columns

Name

Type

Description

table_name

character varying(128)

Table name.

column_name

character varying(128)

Column name.

num_distinct

numeric

Number of different values in a column.

low_value

raw

Low value in a column.

high_value

raw

High value in a column.

density

numeric
  • If there is a histogram on COLUMN_NAME, this column displays the selectivity of values in the histogram that span less than two endpoints. It does not represent the selectivity of values that span two or more endpoints.
  • If no histogram is available on COLUMN_NAME, the value of this column is 1/NUM_DISTINCT.

num_nulls

numeric

Number of empty values in a column.

num_buckets

numeric

Number of buckets in the histogram of a column.

sample_size

numeric

Sample size used to analyze a column.

last_analyzed

timestamp(0) without time zone

Date when a column was last analyzed. Database restart is not supported. Otherwise, data loss will occur.

global_stats

character varying(3)

Not supported. Its value is NULL.

user_stats

character varying(3)

Not supported. Its value is NULL.

notes

character varying(99)

Not supported. Its value is NULL.

avg_col_len

numeric

Average length of a column, in bytes.

histogram

character varying(15)
Specifies whether the histogram exists and the type of the histogram if it exists.
  • NONE: no histogram.
  • FREQUENCY: frequency histogram.
  • EQUI-WIDTH: equal-width histogram.

scope

character varying(7)

For statistics collected on any table other than global temporary tables, the value is SHARED (indicating that the statistics are shared among all sessions).

schema

character varying(64)

Name of the namespace to which the column belongs.
Parent topic: System Views