316 lines
3.7 KiB
Markdown
316 lines
3.7 KiB
Markdown
---
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title: Keywords
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---
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There are about 200 keywords reserved by TDengine, they can't be used as the name of database, STable or table with either upper case, lower case or mixed case.
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## Keywords List
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### A
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- ABORT
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- ACCOUNT
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- ACCOUNTS
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- ADD
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- AFTER
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- ALL
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- ALTER
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- AND
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- AS
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- ASC
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- ATTACH
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### B
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- BEFORE
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- BEGIN
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- BETWEEN
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- BIGINT
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- BINARY
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- BITAND
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- BITNOT
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- BITOR
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- BLOCKS
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- BOOL
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- BY
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### C
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- CACHE
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- CACHELAST
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- CASCADE
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- CHANGE
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- CLUSTER
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- COLON
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- COLUMN
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- COMMA
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- COMP
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- COMPACT
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- CONCAT
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- CONFLICT
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- CONNECTION
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- CONNECTIONS
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- CONNS
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- COPY
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- CREATE
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- CTIME
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### D
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- DATABASE
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- DATABASES
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- DAYS
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- DBS
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- DEFERRED
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- DELETE
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- DELIMITERS
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- DESC
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- DESCRIBE
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- DETACH
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- DISTINCT
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- DIVIDE
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- DNODE
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- DNODES
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- DOT
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- DOUBLE
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- DROP
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### E
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- END
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- EQ
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- EXISTS
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- EXPLAIN
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### F
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- FAIL
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- FILE
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- FILL
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- FLOAT
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- FOR
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- FROM
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- FSYNC
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### G
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- GE
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- GLOB
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- GRANTS
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- GROUP
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- GT
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### H
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- HAVING
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### I
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- ID
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- IF
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- IGNORE
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- IMMEDIA
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- IMPORT
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- IN
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- INITIAL
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- INSERT
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- INSTEAD
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- INT
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- INTEGER
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- INTERVA
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- INTO
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- IS
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- ISNULL
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### J
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- JOIN
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### K
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- KEEP
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- KEY
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- KILL
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### L
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- LE
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- LIKE
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- LIMIT
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- LINEAR
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- LOCAL
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- LP
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- LSHIFT
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- LT
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### M
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- MATCH
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- MAXROWS
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- MINROWS
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- MINUS
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- MNODES
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- MODIFY
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- MODULES
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### N
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- NE
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- NONE
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- NOT
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- NOTNULL
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- NOW
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- NULL
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### O
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- OF
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- OFFSET
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- OR
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- ORDER
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### P
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- PARTITION
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- PASS
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- PLUS
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- PPS
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- PRECISION
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- PREV
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- PRIVILEGE
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### Q
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- QTIME
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- QUERIE
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- QUERY
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- QUORUM
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### R
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- RAISE
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- REM
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- REPLACE
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- REPLICA
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- RESET
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- RESTRIC
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- ROW
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- RP
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- RSHIFT
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### S
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- SCORES
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- SELECT
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- SEMI
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- SESSION
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- SET
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- SHOW
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- SLASH
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- SLIDING
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- SLIMIT
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- SMALLIN
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- SOFFSET
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- STable
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- STableS
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- STAR
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- STATE
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- STATEMEN
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- STATE_WI
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- STORAGE
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- STREAM
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- STREAMS
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- STRING
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- SYNCDB
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### T
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- TABLE
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- TABLES
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- TAG
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- TAGS
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- TBNAME
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- TIMES
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- TIMESTAMP
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- TINYINT
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- TOPIC
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- TOPICS
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- TRIGGER
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- TSERIES
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### U
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- UMINUS
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- UNION
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- UNSIGNED
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- UPDATE
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- UPLUS
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- USE
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- USER
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- USERS
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- USING
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### V
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- VALUES
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- VARIABLE
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- VARIABLES
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- VGROUPS
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- VIEW
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- VNODES
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### W
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- WAL
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- WHERE
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### _
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- _C0
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- _QSTART
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- _QSTOP
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- _QDURATION
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- _WSTART
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- _WSTOP
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- _WDURATION
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## Explanations
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### TBNAME
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`TBNAME` can be considered as a special tag, which represents the name of the subtable, in a STable.
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Get the table name and tag values of all subtables in a STable.
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```mysql
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SELECT TBNAME, location FROM meters;
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```
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Count the number of subtables in a STable.
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```mysql
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SELECT COUNT(TBNAME) FROM meters;
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```
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Only filter on TAGS can be used in WHERE clause in the above two query statements.
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```mysql
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taos> SELECT TBNAME, location FROM meters;
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tbname | location |
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==================================================================
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d1004 | California.SanFrancisco |
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d1003 | California.SanFrancisco |
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d1002 | California.LosAngeles |
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d1001 | California.LosAngeles |
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Query OK, 4 row(s) in set (0.000881s)
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taos> SELECT COUNT(tbname) FROM meters WHERE groupId > 2;
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count(tbname) |
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========================
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2 |
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Query OK, 1 row(s) in set (0.001091s)
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```
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### _QSTART/_QSTOP/_QDURATION
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The start, stop and duration of a query time window.
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### _WSTART/_WSTOP/_WDURATION
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The start, stop and duration of aggegate query by time window, like interval, session window, state window.
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### _c0/_ROWTS
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_c0 is equal to _ROWTS, it means the first column of a table or STable.
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