SELECT-запрос

[WITH expr_list(subquery)]
SELECT [DISTINCT [ON (column1, column2, ...)]] expr_list
[FROM [db.]table | (subquery) | table_function] [FINAL]
[SAMPLE sample_coeff]
[ARRAY JOIN ...]
[GLOBAL] [ANY|ALL|ASOF] [INNER|LEFT|RIGHT|FULL|CROSS] [OUTER|SEMI|ANTI] JOIN (subquery)|table [(alias1 [, alias2 ...])] (ON <expr_list>)|(USING <column_list>)
[PREWHERE expr]
[WHERE expr]
[GROUP BY expr_list] [WITH ROLLUP|WITH CUBE] [WITH TOTALS]
[HAVING expr]
[WINDOW window_expr_list]
[QUALIFY expr]
[ORDER BY expr_list] [WITH FILL] [FROM expr] [TO expr] [STEP expr] [INTERPOLATE [(expr_list)]]
[LIMIT [offset_value, ]n BY columns]
[LIMIT [n, ]m] [WITH TIES]
[LIMIT [n] AFTER start_expr [ALL] [UNTIL end_expr] | LIMIT [n] UNTIL end_expr]
[SETTINGS ...]
[UNION  ...]
[INTO OUTFILE filename [TRUNCATE] [COMPRESSION type [LEVEL level]] ]
[FORMAT format]

FROM table
|> WHERE x > 1
|> AGGREGATE count() AS c GROUP BY y
|> ORDER BY c DESC

COLUMNS('regexp')

CREATE TABLE default.col_names (aa Int8, ab Int8, bc Int8) ENGINE = TinyLog

SELECT COLUMNS('a') FROM col_names

┌─aa─┬─ab─┐
│  1 │  1 │
└────┴────┘

SELECT COLUMNS('a'), COLUMNS('c'), toTypeName(COLUMNS('c')) FROM col_names

┌─aa─┬─ab─┬─bc─┬─toTypeName(bc)─┐
│  1 │  1 │  1 │ Int8           │
└────┴────┴────┴────────────────┘

SELECT COLUMNS('a') + COLUMNS('c') FROM col_names

Received exception from server (version 19.14.1):
Code: 42. DB::Exception: Received from localhost:9000. DB::Exception: Number of arguments for function plus does not match: passed 3, should be 2.

SELECT * ILIKE 'a%' FROM col_names

┌─aa─┬─ab─┐
│  1 │  1 │
└────┴────┘

SELECT * ILIKE 'a_' FROM col_names

SELECT t.* ILIKE 'a%' EXCEPT (ab) FROM col_names AS t

┌─aa─┐
│  1 │
└────┘

SELECT COLUMNS('[jk]') APPLY(toString) APPLY(length) APPLY(max) FROM columns_transformers;

┌─max(length(toString(j)))─┬─max(length(toString(k)))─┐
│                        2 │                        3 │
└──────────────────────────┴──────────────────────────┘

SELECT * REPLACE(i + 1 AS i) EXCEPT (j) APPLY(sum) from columns_transformers;

┌─sum(plus(i, 1))─┬─sum(k)─┐
│             222 │    347 │
└─────────────────┴────────┘

SELECT * FROM some_table SETTINGS optimize_read_in_order=1, cast_keep_nullable=1;