7.14 APPROX_COUNT_DISTINCT
摘要
APPROX_COUNT_DISTINCT返回包含expr不同值的行数。处理大量数据的速度明显快于COUNT，与精确结果的偏差可以忽略不计。
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Oracle 20C官方文档-SQL Language Reference
- 目录
- 7 Oracle 函数
- 7.9 ABS
- 7.10 ACOS
- 7.11 ADD_MONTHS
- 7.12 ANY_VALUE
- 7.13 APPROX_COUNT
- 7.14 APPROX_COUNT_DISTINCT
- 7.15 APPROX_COUNT_DISTINCT_AGG
- 7.16 APPROX_COUNT_DISTINCT_DETAIL
- 7.17 APPROX_MEDIAN
- 7.18 APPROX_PERCENTILE
- 7.19 APPROX_PERCENTILE_AGG
- 7.20 APPROX_PERCENTILE_DETAIL
- 7.21 APPROX_RANK
- 7.22 APPROX_SUM
- 7.23 ASCII
- 7.24 ASCIISTR
- 7.25 ASIN
- 7.27 ATAN2
- 7.28 AVG
- 7.26 ATAN
- 7.29 BFILENAME
- 7.30 BIN_TO_NUM
- 7.31 BITAND
- 7.32 BIT_AND_AGG
- 7.33 BITMAP_BIT_POSITION
- 7.34 BITMAP_BUCKET_NUMBER
- 7.35 BITMAP_CONSTRUCT_AGG
- 7.36 BITMAP_COUNT
- 7.37 BITMAP_OR_AGG
- 7.39 BIT_XOR_AGG
- 7.40 CARDINALITY
- 7.42 CEIL
- 7.43 CHARTOROWID
- 7.44CHECKSUM
- 7.45 CHR
- 7.47 CLUSTER_DISTANCE
- 7.46 CLUSTER_DETAILS
- 7.48 CLUSTER_ID
- 7.49 CLUSTER_PROBABILITY
- 7.50 CLUSTER_SET
- 7.51 COALESCE
- 7.52 COLLATION
- 7.53 COLLECT
- 7.54 COMPOSE
- 7.55 CON_DBID_TO_ID
- 7.56 CON_GUID_TO_ID
- 7.57 CON_NAME_TO_ID
- 7.58 CON_UID_TO_ID
- 7.59 CONCAT
- 7.60 CONVERT
- 7.61 CORR
- 7.62 CORR_*
- 7.63 COS
- 7.64 COSH
- 7.65 COUNT
- 7.66 COVAR_POP
- 7.67 COVAR_SAMP
- 7.68 CUBE_TABLE
- 7.69 CUME_DIST
- 7.70 CURRENT_DATE
- 7.71 CURRENT_TIMESTAMP
- 7.72 CV
- 7.73 DATAOBJ_TO_MAT_PARTITION
- 7.74 DATAOBJ_TO_PARTITION
- 7.75 DBTIMEZONE
- 7.76 DECODE
- 7.41 CAST
- 7.78 DENSE_RANK
- 7.81 DUMP
- 7.79 DEPTH
- 7.80 DEREF
- 7.82 EMPTY_BLOB, EMPTY_CLOB
- 7.83 EXISTSNODE
- 7.84 EXP
- 7.85 EXTRACT (datetime)
- 7.86 EXTRACT (XML)
- 7.87 EXTRACTVALUE
- 7.88 FEATURE_COMPARE
- 7.89 FEATURE_DETAILS
- 7.90 FEATURE_ID
- 7.91 FEATURE_SET
- 7.92 FEATURE_VALUE
- 7.93 FIRST
- 7.94 FIRST_VALUE
- 7.95 FLOOR
- 7.96 FROM_TZ
- 7.97 GREATEST
- 7.98 GROUP_ID
- 7.99 GROUPING
- 7.100 GROUPING_ID
- 7.101 HEXTORAW
- 7.102 INITCAP
- 7.103 INSTR
- 7.104 ITERATION_NUMBER
- 7.105 JSON_ARRAY
- 7.106 JSON_ARRAYAGG
- 7.107 JSON Type Constructor
- 7.108 JSON_DATAGUIDE
- 7.109 JSON_MERGEPATCH
- 7.120 LAG
- 7.121 LAST
- 7.122 LAST_DAY
