Functions and Operators

This section describes the functions and operators in M-compatible databases.

The functions and operators in "SQL Reference > Functions and Operators" in Developer Guide are internal APIs in M-compatible databases and are prohibited. Using these functions and operators may produce unexpected results.

Functions listed in the following tables are not supported in M-compatible databases. For details, see "SQL Reference > Functions and Operators" in Developer Guide.

**Table 1** Functions with the same names as those in MySQL and not supported by M-compatible databases
cot	isEmpty	json_append	json_array	json_array_append
json_array_insert	json_contains	json_contains_path	json_depth	json_extract
json_insert	json_keys	json_length	json_merge	json_merge_patch
json_merge_preserve	json_object	json_quote	json_remove	json_valid
json_replace	json_search	json_set	json_type	json_unquote
last_insert_id	md5	mod	octet_length	overlaps
point	radians	stddev_pop	stddev_samp	var_pop
var_samp	variance	lag	lead	-

**Table 2** System information functions
adm_hist_snapshot_func	adm_hist_sqlstat_func	adm_hist_sqltext_func	session_context

**Table 3** Statistics information functions
get_global_transactions_prepared_xacts	get_global_transactions_running_xacts

**Table 4** System administration functions
dbe_perf.get_full_sql_by_parent_id_and_timestamp	dbe_perf.get_active_session_profile	dbe_perf.get_global_slow_sql_by_timestamp	dbe_perf.get_global_full_sql_by_timestamp

**Table 5** Other functions
information_schema_pg_truetypid	information_schema._pg_truetypmod	summary_create	sys_context

**Table 6** Internal functions
db4ai.archive_snapshot	db4ai.create_snapshot	db4ai.create_snapshot_internal	db4ai.manage_snapshot_internal	db4ai.prepare_snapshot
db4ai.prepare_snapshot_internal	db4ai.publish_snapshot	db4ai.purge_snapshot	db4ai.purge_snapshot_internal	db4ai.sample_snapshot

**Table 7** Deprecated functions
pgxc_get_stat_dirty_tables	gs_wIm_persistent_user_resource_info

**Table 8** User-defined GaussDB functions
pg_catalog.ts_debug	pg_catalog.gs_check_logic_cluster_consistency	pg_catalog.gs_check_tables_distribution	pg_catalog.gs_wlm_persistent_user_resource_info	pg_catalog.create_wlm_instance_statistics_info
pg_catalog.pgxc_get_wlm_current_instance_info	pg_catalog.pgxc_get_wlm_history_instance_info	pg_catalog.pgxc_get_wlm_session_info_bytime	pg_catalog.create_wlm_session_info	pg_catalog.to_char
pg_catalog.to_nchar	pg_catalog.report_application_error	pg_catalog.to_text	pg_catalog.time_text	pg_catalog.timetz_text
pg_catalog.reltime_text	pg_catalog.abstime_text	pg_catalog.int1	pg_catalog.int2	pg_catalog.int4
pg_catalog.int8	pg_catalog.float4	pg_catalog.float8	pg_catalog.to_numeric	pg_catalog.to_integer
pg_catalog.rawtohex	pg_catalog.to_clob	pg_catalog.trunc	pg_catalog.to_varchar2	pg_catalog.to_interval
pg_catalog.to_ts	pg_catalog.timestamp_to_smalldatetime	pg_catalog.smalldatetime_to_timestamp	pg_catalog.smalldatetime_to_varchar2	pg_catalog.varchar2_to_smalldatetime
pg_catalog.bpchar_to_smalldatetime	pg_catalog.abstime_to_smalldatetime	pg_catalog.smalldatetime_to_abstime	pg_catalog.smalldatetime_to_time	pg_catalog.smalldatetime_to_timestamptz
pg_catalog.timestamptz_to_smalldatetime	pg_catalog.regexp_like	pg_catalog.intervaltonum	pg_catalog.to_nvarchar2	pg_catalog.invalidate_plsql_object
pg_catalog.table_skewness	pg_catalog.pgxc_xacts_iscommitted	pg_catalog.pgxc_parse_clog	pg_catalog.pgxc_get_senders_catchup_time	pg_catalog.global_transaction
pg_catalog.gs_stat_reset	pg_catalog.pgxc_fenced_udf_process	pg_catalog.pgxc_terminate_all_fenced_udf_process	pg_catalog.create_wlm_operator_info	pg_catalog.copy_error_log_create
pg_catalog.get_delta_info	pg_catalog.pgxc_stat_bad_block_clear	pg_catalog.pgxc_query_audit	pg_catalog.is_oid_in_group_members	pg_catalog.get_shard_oids_byname
pg_catalog.reload_active_coordinator	pg_catalog.lock_cluster_ddl	pg_catalog.unlock_cluster_ddl	pg_catalog.pgxc_get_stat_dirty_tables	pg_catalog.pgxc_get_stat_dirty_tables
pg_catalog.get_large_table_name	pg_catalog.global_segment_space_info	dbe_perf.get_global_full_sql_by_timestamp	dbe_perf.get_global_slow_sql_by_timestamp	dbe_perf.get_full_sql_by_parent_id_and_timestamp
dbe_perf.global_plancache_clean	dbe_perf.global_slow_query_info_bytime	dbe_perf.get_global_gs_asp	dbe_perf.get_datanode_active_session	dbe_perf.get_datanode_active_session_hist
dbe_perf.global_stat_activity_timeout	dbe_perf.get_active_session_profile	dbe_perf.generate_asp_report	-	-

Functions listed in Table 8 are user-defined GaussDB functions and are not recommended because their behavior in M compatibility is unknown.

Operator Overview
Logical Operators
Bitwise Operators
Pattern Matching Operators
Comparison Functions and Comparison Operators
Numeric Operation Functions and Arithmetic Operators
String Functions
Datetime Functions
Type Conversion Functions
Aggregate Functions
Encryption and Decryption Functions
Process Control Functions
Internal Functions
Other Functions

Parent topic: SQL Reference

Previous topic: VACUUM

Next topic: Operator Overview

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