Here is a summary of rules for identifiers:
Table 1. BigQuery Identifiers
| Identifier | Length | Matching Regular Expression |
|---|---|---|
| projectId | 6-30 | ^[a-z][-a-z0-9]{4,28}[a-z0-9]$ |
| datasetId | 1-1024 | ^[a-zA-Z0-9_]{1,1024}$ |
| tableId | 1-1024 | ^[a-zA-Z0-9_]{1,1024}$ |
| field name | 1-128 | ^[a-zA-Z_][a-zA-Z0-9_]{1,127}$ |
See links below for references.