与上面的 coalesce()类似。 last_insert_rowid() 返回当前数据库连接最后插入行的ROWID。sqlite_last_insert_rowid() API函数同样可用于得到该值。 length(X) 返回X的长度,以字符计。如果SQLite被配置为支持UTF-8,则返回UTF-8字符数而不是字节数。 like(X,Y [,Z]) 用于实现SQL语法"X LIKE Y [ESCAPE...
IndexOnly Scan IndexOnly Scan 是覆盖索引扫描,所需的返回结果能被所扫描的索引全部覆盖,例如上面Index Scan中的SQL 把“select * ” 修改为“select st_no” ,其EXPLAIN 结果输出如下: postgres=> explain(ANALYZE,VERBOSE,BUFFERS) select st_no from class where st_no=2; QUERY PLAN --- Index Only Sca...
为NULL返回指定值 select sal, coalesce(comm, 0) from emp; select sal, nvl(comm, 0) from emp; 条件查询 -- isnull(a) isnotnull(a) select * from emp where isnull(comm); select * from emp where isnotnull(comm); -- nullif(x, y) 相等为空,否则为a SELECT nullif("b", "b"), n...
row *** stage: 1 node: 0 plan: CoalesceBatchesExec: target_batch_size=8192 metrics=[output_rows: 0, elapsed_compute: 4147, ] FilterExec: host@2 = host1 metrics=[output_rows: 0, elapsed_compute: 32, ] RepartitionExec: partitioning=RoundRobinBatch(32), input_partitions=8 metrics=[repa...
I have figured it out. I should have usedUNION ALLinstead ofUNION.
, COALESCE(CAST(CAST(O.Total_Cost AS BIGINT) AS VARCHAR(254)), '') Cost , path FROM tree LEFT JOIN ( SELECT i.source_id , i.target_id , CAST(CAST(ROUND(o.stream_count) AS BIGINT) AS VARCHAR(12)) || ' of ' || CAST (total_rows AS VARCHAR(12)) ...
(NULL::STRING)::REFCURSOR, " col 1_12" = '1989-11-29':::DATE, col1_2 = tab_27.col1_2; │ SELECT e'pachycephalosaurus\x05p>K)':::STRING AS col_39, COALESCE(NULL, tab_29.col1_2) AS col_40, '2026-11-18 22:29:17.000266':::TIMESTAMP AS col_41, tab_29.col1_2 AS ...
NVLe COALESCE NVL2 NULLIF Funzioni di formattazione del tipo di dati CAST CONVERT AL_ CHAR TO_ DATE AL_ NUMBER TEXT_PER_ _ INT ALT TEXT_PER_ _ NUMERIC ALT Stringhe di formato datetime Stringhe di formato numerico Formattazione in stile Teradata per i dati numerici Funzioni di data e ...
Coalesces joins. Chooses join order and implementation. Fuses adjacent operations. Removes redundant operations. Pushes down predicates. Evaluates any operations on constants.From optimized plan to physical planIn this stage, the planner:Maps plan operators to differential dataflow operators. Locates ...
UseCOALESCEon the results of twoLEFT JOINS Use the combination of methods above: aLEFT JOINforFrenchnames and a subquery forEnglishones Efficiency of each of these method depends of the fallback probability (how many items are covered by the localization). ...