. . . . . . . . . . . . . . . . . . . . . . 295 7.9 In SQLSever and PostgreSQL, why does the aggregation column without alias throw ex‐ ception? . . . . . . . . . . . . . . . . . . . . . . . . . . . extract the parsing context, which can include tables, options, ordering items, grouping items, aggregation functions, pagination information, query conditions and placeholders that may be revised. Query order_id ORDER BY user_id, order_item_id; Another situation of column derivation is using AVG aggregation function. In distributed situations, it is not right to calculate the average value with avg1

257 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262 Pagination Merger . . . . . . . . . . . . . . 308 7.7.20 20. [Other] In SQLSever and PostgreSQL, why does the aggregation column with‐ out alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . DML, DDL, DCL, TCL and most regular DAL. Support complex query with pagination, DISTINCT, ORDER BY, GROUP BY, aggregation and table JOIN. Regular Query • SELECT Clause SELECT select_expr [, select_expr

267 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 Pagination Merger . . . . . . . . . . . . . . . . 351 7.8.23 [Other] In SQLSever and PostgreSQL, why does the aggregation column without alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . . DML, DDL, DCL, TCL and most regular DAL. Support complex query with pagination, DISTINCT, ORDER BY, GROUP BY, aggregation and table JOIN. Regular Query • SELECT Clause SELECT select_expr [, select_expr

278 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 Pagination Merger . . . . . . . . . . . . . . . . 363 7.8.23 [Other] In SQLSever and PostgreSQL, why does the aggregation column without alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . . DML, DDL, DCL, TCL and most regular DAL. Support complex query with pagination, DISTINCT, ORDER BY, GROUP BY, aggregation and table JOIN. Support PostgreSQL and openGauss database SCHEMA DDL and DML statements

382 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387 Pagination Merger . . . . . . . . . . . . . . . . . . 461 8.6.3 Other In SQLSever and PostgreSQL, why does the aggregation column without alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . . and common DALs. Support for complex queries such as paging, de‐duplication, sorting, grouping, aggregation, table association, etc. Support SCHEMA DDL and DML statements of PostgreSQL and openGauss database

409 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414 Pagination Merger . . . . . . . . . . . . . . . . . . 500 8.6.3 Other In SQLSever and PostgreSQL, why does the aggregation column without alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . . provides complex data query and analysis capabilities across data sources, simpli‐ fying the data aggregation from different data locations. Data En‐ cryp‐ tion Data Encryption is a basic way to ensure

521 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526 Pagination Merger . . . . . . . . . . . . . . . 553 xii 13.6.3 Other In SQLSever and PostgreSQL, why does the aggregation column without alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . . provides complex data query and analysis capabilities across data sources, simpli‐ fying the data aggregation from different data locations. Da ta En cr yp ti on Data Encryption is a basic way to ensure

550 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555 Pagination Merger . . . . . . . . . . . . . . . . . 582 13.6.3 Other In SQLSever and PostgreSQL, why does the aggregation column without alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . . provides complex data query and analysis capabilities across data sources, simpli‐ fying the data aggregation from different data locations. Da ta En cr yp ti on Data Encryption is a basic way to ensure

[ASC | DESC], ...] [LIMIT {[offset,] row_count | row_count OFFSET offset}] • select_expr * | [DISTINCT] COLUMN_NAME [AS] [alias] | (MAX | MIN | SUM | AVG)(COLUMN_NAME | alias) [AS] [alias] | COUNT(* tbl_name WHERE col2 = ? GROUP BY col1 ORDER BY col3 DESC LIMIT ?, ? SELECT DISTINCT * FROM tbl_name WHERE col1 = ? SELECT COUNT(DISTINCT col1) FROM tbl_name SELECT subquery_alias.col1 FROM (select tbl_name FROM tbl_name1 UNION ALL SELECT * FROM tbl_name2 UNION ALL SELECT SUM(DISTINCT col1), SUM(col1) FROM tbl_name 详见 DISTINCT 支持情况详细说明 SELECT * FROM tbl_name WHERE to_date(create_time, ‘yyyy‐mm‐dd’)

allocation of resources • Resource Assign – Execute job on suitable time and assigned resources – Aggregation same job to same job executor – Append resources to newly assigned jobs dynamically • Job Governance