[IMPALA-10173] Allow implicit casts between numeric and string types when inserting into table

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Done
• Fix Version/s: Impala 4.3.0
• Component/s: Frontend
• Labels: 2023Q1 ramp-up sql-language supportability
• Target Version: Product Backlog
• Epic Color: ghx-label-1
• Assignee: Peter Rozsa
• Reporter: Tim Armstrong
• Created: 17/Sep/20 21:58
• Updated: 26/Mar/24 23:05
• Resolved: 30/Jun/23 08:50

Description

Impala is somewhat stricter than other engines such as Hive when it comes into implicit casts. This avoids a lot of ambiguity and edge cases with complex SQL, but we could consider loosening it for simple cases like inserting into a table where the meaning/intent is pretty straightforward.

Repro

CREATE TABLE iobt (   c0 FLOAT ) ;
INSERT INTO iobt(c0) VALUES ('0'), (1562998803);

Error

AnalysisException: Incompatible return types 'STRING' and 'INT' of exprs ''0'' and '1562998803'.

Issue Links

• causes: IMPALA-12285 Type mismatch in set operations with ALLOW_UNSAFE_CASTS enabled
• causes: IMPALA-12386 NullExpr substitution failure with unsafe casts enabled
• causes: IMPALA-12384 Restore NullLiteral's uncheckedCastTo function signature
• is related to: IMPALA-12386 NullExpr substitution failure with unsafe casts enabled
• relates to: IMPALA-3217 Allow text quoted by single quotes be treated as a literal value of char/varchar