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- Constraints – DuckDB 13142
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...example, we could enforce that the name column does not contain spaces using the following CHECK constraint. CREATE TABLE students ( name VARCHAR CHECK ( NOT contains ( name , ' ' ))); INSERT INTO students VALUES ( 'this name contains spaces' ); Constra...int Error: CHECK constraint failed on table students with expression CHECK((NOT contains("name", ' '))) Not Null Constraint A not-null constraint specifies that the column can...ables are nullable. Adding NOT NULL to a column definition enforces that a column cannot contain NULL values. CREATE TABLE students ( name VARCHAR NOT NULL ); INSERT INTO students VALUES ( NULL ); Constraint Error: NOT NULL constraint failed: students.na... - https://man.mtool.work/duckdb/1.3/sql/constraints.html
- GROUPING SETS – DuckDB 8810
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...); Description GROUPING SETS perform the same aggregate across different GROUP BY clauses in a single query. CREATE TABLE students ( course VARCHAR , type VARCHAR ); INSERT INTO students ( course , type ) VALUES ( 'CS' , 'Bachelor' ), ( 'CS' , 'Bachelor...D' ), ( 'Math' , 'Masters' ), ( 'CS' , NULL ), ( 'CS' , NULL ), ( 'Math' , NULL ); SELECT course , type , count ( * ) FROM students GROUP BY GROUPING SETS (( course , type ), course , type , ()); course type count_star() Math NULL 1 NULL NULL 7 CS PhD 1...ivalent to the following statement of UNION ALL clauses: -- Group by course, type: SELECT course , type , count ( * ) FROM students GROUP BY course , type UNION ALL -- Group by type: SELECT NULL AS course , type , count ( * ) FROM students GROUP BY type... - https://man.mtool.work/duckdb/1.3/sql/query_syntax/grouping_sets.html
- EXPLAIN: Inspect Query Plans – DuckDB 8481
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...zer transforms the existing physical plan into a better physical plan. To demonstrate, see the below example: CREATE TABLE students ( name VARCHAR , sid INTEGER ); CREATE TABLE exams ( eid INTEGER , subject VARCHAR , sid INTEGER ); INSERT INTO students V...exams VALUES ( 10 , 'Physics' , 1 ), ( 20 , 'Chemistry' , 2 ), ( 30 , 'Literature' , 3 ); EXPLAIN ANALYZE SELECT name FROM students JOIN exams USING ( sid ) WHERE name LIKE 'Ma%' ; ┌─────────────────────────────┐ │┌───────────────────────────┐│ ││ Physic...─────────────────────┘└─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ SEQ_SCAN │ │ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ │ │ students │ │ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ │ │ sid │ │ name │ │ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ │ │ Filters: name>=Ma AND name│ │ <Mb AND name IS NOT... - https://man.mtool.work/duckdb/1.3/guides/meta/explain.html
- EXPLAIN ANALYZE: Profile Queries – DuckDB 8481
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...f all the times spent on the individual operators. Below is an example of running EXPLAIN ANALYZE on a query: CREATE TABLE students ( name VARCHAR , sid INTEGER ); CREATE TABLE exams ( eid INTEGER , subject VARCHAR , sid INTEGER ); INSERT INTO students V...exams VALUES ( 10 , 'Physics' , 1 ), ( 20 , 'Chemistry' , 2 ), ( 30 , 'Literature' , 3 ); EXPLAIN ANALYZE SELECT name FROM students JOIN exams USING ( sid ) WHERE name LIKE 'Ma%' ; ┌─────────────────────────────────────┐ │┌───────────────────────────────...─────────────────────┘└─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ SEQ_SCAN │ │ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ │ │ students │ │ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ │ │ sid │ │ name │ │ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ │ │ Filters: name>=Ma AND name│ │ <Mb AND name IS NOT... - https://man.mtool.work/duckdb/1.3/guides/meta/explain_analyze.html
- Profiling – DuckDB 8243
- This page is for DuckDB 1.3, which is outdated. Switch to the current version . Search Shortcut cmd + k | ctrl + k Installation Documentation Getting Started Connect Overview Concurrency Data Import Overview Data Sources CSV Files Overview
...filing and set the output to a file. We only enable EXTRA_INFO , OPERATOR_CARDINALITY , and OPERATOR_TIMING . CREATE TABLE students ( name VARCHAR , sid INTEGER ); CREATE TABLE exams ( eid INTEGER , subject VARCHAR , sid INTEGER ); INSERT INTO students V...{"CPU_TIME": "false", "EXTRA_INFO": "true", "OPERATOR_CARDINALITY": "true", "OPERATOR_TIMING": "true"}' ; SELECT name FROM students JOIN exams USING ( sid ) WHERE name LIKE 'Ma%' ; The file's content after executing the query: { "extra_info" : {}, "query..._name" : "SELECT name \n FROM students \n JOIN exams USING (sid) \n WHERE name LIKE 'Ma%';" , "children" : [ { "operator_timing" : 0.000001 , "operator_cardinali... - https://man.mtool.work/duckdb/1.3/dev/profiling.html
- Information Schema – DuckDB 7622
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...ema Name of the schema that contains the constraint VARCHAR 'main' constraint_name Name of the constraint VARCHAR 'exam_id_students_id_fkey' key_column_usage : Key Column Usage Column Description Type Example constraint_catalog Name of the database that..._schema Name of the schema containing the constraint. VARCHAR main constraint_name Name of the constraint. VARCHAR exam_id_students_id_fkey unique_constraint_catalog Name of the database that contains the unique or primary key constraint that the foreign...' unique_constraint_name Name of the unique or primary key constraint that the foreign key constraint references. VARCHAR 'students_id_pkey' match_option Match option of the foreign key constraint. Always NONE . VARCHAR NONE update_rule Update rule of th... - https://man.mtool.work/duckdb/1.3/sql/meta/information_schema.html
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