Functions and Operators

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

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 but not supported by M-compatible databases
isEmpty	overlaps	point	regexp_instr	regexp_like
regexp_replace	regexp_substr	stddev_pop	stddev_samp	var_pop
var_samp	variance	-	-	-

When the function regexp_instr, regexp_like, regexp_replace, or regexp_substr is used, if the value of the m_format_dev_version parameter is 's2' or later and the value of the m_format_behavior_compat_options parameter contains 'enable_conflict_funcs', an error is reported, indicating that the behavior is not supported in M-compatible databases. Other behaviors of these functions are the same as those of functions with the same name in "SQL Reference > Functions and Operators > Character Processing Functions and Operators" in Developer Guide.

**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